Wilcoxon-Mann-Whitney odds ratio: A statistical measure for ordinal outcomes such as EDSS

BACKGROUND

In many clinical situations, ordinal scales afford the primary method of semi-quantifying patient outcomes. In the field of multiple sclerosis, the primary ordinal scale is the Expanded Disability Status Scale. Predominant methods of ordinal scale statistical analysis provide a p-value without effect size or rely heavily on the assumption of proportionality of odds, subjecting them to lack of power and error. The Wilcoxon-Manny-Whitney Odds is a statistical method which provides significant information such as p-value, effect size, number needed to treat, confidence intervals, and is largely assumption-free. However, its utility has not been demonstrated in the field of multiple sclerosis.

METHODS

Three clinical studies in the field of multiple sclerosis were selected which utilized ordinal scale outcomes at group or individual levels. Data from these studies was extracted using WebPlotDigitizer, and a custom Wilxocon-Mann-Whitney Odds software was applied to each dataset to re-analyze the main outcomes of the studies.

RESULTS

Re-analysis of the manuscript by Muraro et al., 2017 demonstrated that autologous stem cell transplantation for relapsing remitting multiple sclerosis resulted in a 65% chance of improving from any Expanded Disability Status Scale category, although not significant. Re-analysis of the manuscript by Songthammawat et al., 2019 demonstrated chance of improvement with intravenous methylprednisolone and concurrent plasma exchange was 185% versus 32% in intravenous methylprednisolone with add-on plasma exchange, although not significant. Re-analysis of Kister et al., 2012 demonstrated the chances of mobility or cognition scores generally favored decline at every 5-year increment of study, and although statistically significant, these were smaller effect sizes ranging from an 11% chance of improvement to a 66% chance of decline over a 5-year interval.

DISCUSSION

The Wilcoxon-Mann-Whitney Odds simplifies ordinal data analysis with its robust largely assumption-free nature. In the place of numerous statistical tests, this single test provides effect size estimate, number needed to treat, p-values, and confidence intervals. Importantly, the Wilcoxon-Mann-Whitney Odds effect size calculation is intuitively applicable to both individual and population-levels. Further, the Wilcoxon-Mann-Whitney Odds allows intuitive description of the progression of large cohorts over time, and we were able to clearly convey the odds of mobility and cognitive decline over 30 years in a large multiple sclerosis cohort. Overall, the Wilcoxon-Mann-Whitney Odds is a powerful and robust statistical test with significant promise within the field of multiple sclerosis.

Radiologic Analysis of C2 to Predict Safe Placement of Pedicle Screws

Background

Preoperative assessment of C2 pedicle morphology is critical to safe pedicle screw placement. To avoid iatrogenic injury, complex digital templating software has been introduced; however, this technology may not be available in many centers. We report a technique for preoperative assessment of C2 pedicle screw placement safety based upon 2-dimensional sagittal computed tomography (CT) scan images and verify its utility in clinical practice.

Methods

A total of 46 consecutive patients underwent cervical spine CT scans between 2005 and 2011. The C2 pedicle morphology was assessed on sagittal CT imaging by 5 independent reviewers to determine the feasibility and risk associated with pedicle screw placement. Thirty consecutive patients underwent C2 pedicle screw placement and were followed clinically for a minimum of 2 years. The ability to place a screw was noted, and accuracy of screw placement was assessed postoperatively by CT scan.

Results

The CT scan analysis demonstrated that 11% (5/46) of patients had sufficient pedicle size bilaterally to allow safe placement of long pedicle screws with a low risk of vertebral artery injury, whereas 15% (7/46) were considered a high risk bilaterally. Screw placement was deemed low risk in 28%, moderate risk in 38%, and high risk in 34%. Excellent intraobserver reliability and good interobserver reliability was observed. Clinically, 18 of 20 (90%) low-risk and 21 of 24 (88%) moderate-risk pedicle screws were placed safely versus 5 of 16 (31%) high-risk pedicle screws (P < .001).

Conclusions

Using the described technique for evaluating the C2 pedicle via sagittal CT scan images allows for safe and reliable pedicle screw placement without relying upon complex digital templating software, which may have limited availability.

Level of Evidence

II.

Clinical Relevance

This study aids in the surgical decision-making behind the placement of C2 pedicle screws using CT scans without reliance upon complex digital templating software.

Ocular manifestations of Seckel syndrome

PURPOSE

To report ophthalmic findings in three siblings with Seckel syndrome.

METHODS

Observational case report. Three siblings with Seckel syndrome were examined.

RESULTS

Severe bilateral pigmentary retinopathy with severe myopia and astigmatism was found in all three patients. Electroretinography was performed on the eldest sibling and showed no detectable rod or cone responses.

CONCLUSION

Severe, early onset, bilateral retinal degeneration with severe myopia and astigmatism may be associated with Seckel syndrome.

Surgical alternatives for treatment of obstructive sleep apnoea: review and case series

Obstructive sleep apnoea (OSA) affects up to 24% of middle aged males, resulting in excessive daytime sleepiness, cognitive dysfunction, hypertension, increased risks for acute coronary events, stroke and auto accidents. At special risk are individuals with BMI greater than 29, neck circumference greater than 43 cm (17 inches), macroglossia and retrognathia. Although non-surgical nasal positive air pressure (nCPAP) and mandibular advancement oral appliances are often effective and are the most widely used therapy, they are not definitive for more severe OSA and patients show poor long-term compliance. Surgical reduction of palatal, lingual and nasal soft tissue volumes improve airway functions in approximately 40% of patients with mild to moderate OSA. Maxillary and mandibular advancement osteotomies have proven over the past decade to reverse even severe OSA at greater than the 90% efficacy levels. Surgical treatment targeted to skeletal and airway soft tissue anomalies using a multidisciplinary treatment approach can have a major impact on this widespread and high-risk disorder.

Optic neuritis in children

PURPOSE

To describe the clinical characteristics of optic neuritis in children, including final visual acuity and development of multiple sclerosis (MS).

METHODS

Charts were reviewed of all patients < 15 years of age who presented with optic neuritis to the Bascom Palmer Eye Institute or the Miami Children's Hospital between 1986 and 1998.

RESULTS

Fifteen patients were identified. There was a slight female predilection in the study group (60%), with a mean age of 9.8 years at presentation. A preceding febrile illness within 2 weeks of visual symptoms was reported in 66% of patients. Initial visual acuity ranged from 20/15 to no light perception. Involvement was bilateral in 66% of patients, and disc swelling was present in 64% of involved eyes. Of the patients who underwent magnetic resonance imaging, 33% had focal demyelinating lesions in the brain, and 63% of affected nerves were enlarged or enhanced with gadolinium. Eleven patients were treated with intravenous steroids. Final visual acuity was > or = 20/40 in 58.3% of eyes. Thirty percent of the patients had vision of finger counting or worse. Four (26%) patients developed MS. The mean age of patients with MS was 12 years, compared with 9 years in children who did not develop MS. Patients with unilateral involvement had an excellent visual prognosis (100% > 20/40), but a higher rate of development of MS (75%). Two patients had positive serology for Lyme disease.

CONCLUSIONS

Optic neuritis presents differently in children than in adults. Children typically have bilateral involvement with papillitis following an antecedent viral illness. Although visual prognosis is poorer in children than adults, the development of MS is less common in children. Children who present with unilateral involvement have a better visual prognosis; however, they also develop MS at a greater frequency than children with bilateral involvement. Patients who developed MS were, on average, older at presentation with optic neuritis than those who did not develop MS.

Clinical practice guidelines for the management of orbital cellulitis

PURPOSE

A retrospective study was performed to review the management of periorbital and orbital cellulitis at Miami Children's Hospital, between January 1, 1993 and February 15, 1996.

RESULTS

One hundred and one patients were included in this study. The variables analyzed in this study included age, sex, length of hospital stay, imaging studies, laboratory tests, and microbiology specimens collected. Patients were classified according to the modified Chandler classification. Average length of stay for our patient population was 4.5 days. Data regarding the radiologic studies, laboratory tests, and microbiology yield of specimens were analyzed.

CONCLUSIONS

The incidence of orbital infection, manifested by lid swelling alone is much more common (stages I and II) than orbital infection involving postseptal findings (stages III, IV, and V); 84.16% compared with 15.84%, respectively. An updated approach and a general guideline for the management of periorbital and orbital cellulitis according to the clinical staging of the process is presented.

Relationship between drug use and other problem behaviors in urban adolescents

This study tested the generality of Jessor and Jessor's (1977) problem behavior theory, which states that a variety of problem behaviors constitute a behavioral syndrome in normal adolescents. Relationships among 5 adolescent problem behaviors (cigarette use, alcohol use, marijuana use, delinquency, and sexual intercourse) were examined in 7th-grade boys (n = 556) and girls (n = 715), and 9th-grade boys (n = 481) and girls (n = 485) in an urban school system in which the majority of students were African American and from low-income families. Measures of problem behavior frequency were positively correlated with each other and negatively correlated with several measures of conventional behavior. Confirmatory factor analyses replicated findings of previous studies that a single common factor underlies adolescent problem behaviors.

High prevalence of Kingella kingae in joint fluid from children with septic arthritis revealed by the BACTEC blood culture system

In an effort to improve detection of fastidious organisms, joint fluid aspirates of pediatric patients were inoculated into BACTEC 460 aerobic blood culture bottles, in addition to cultures on solid media. Culture records for the 1988 to 1991 period were reviewed to compare the performance of both methods for the recovery of pathogens. Overall, 216 children underwent a diagnostic joint tap, and 63 specimens grew significant organisms, including Kingella kingae in 14. While both methods were comparable for recovery of usual pathogens, with a single exception, K. kingae isolates were detected by the BACTEC system only. K. kingae appears to be a more common cause of septic arthritis in children than has been previously recognized. The BACTEC blood culture system enhances the recovery of K. kingae from joint fluid and improves bacteriologic diagnosis of pediatric septic arthritis.

Simultaneous split-thickness skin grafting and placement of endosteal implants in the edentulous mandible: a preliminary report

Reconstruction of the edentulous atrophic mandible continues to be a treatment problem for the oral and maxillofacial surgeon. Clearly, endosteal osseointegrated implants are indicated for rehabilitation, but a total implant-supported prosthesis may not always be possible. The implant-supported overdenture is an excellent alternative, but modifications of the unfavorable residual ridge may be necessary. Attached crestal soft tissue, resistant to mechanical trauma, and improvement of the residual ridge anatomy are provided by adding a split-thickness skin graft vestibuloplasty (VSG) and lowering of the floor of the mouth (LFM). Simultaneous VSG and LFM with placement of endosteal implants provides the optimal condition for maximal rehabilitation of the atrophic mandible with specific indications. Results of four skin grafts and eight implants simultaneously placed are reported.

Relationship between drug use and other problem behaviors in urban adolescents

This study tested the generality of Jessor and Jessor's (1977) problem behavior theory, which states that a variety of problem behaviors constitute a behavioral syndrome in normal adolescents. Relationships among 5 adolescent problem behaviors (cigarette use, alcohol use, marijuana use, delinquency, and sexual intercourse) were examined in 7th-grade boys (n = 556) and girls (n = 715), and 9th-grade boys (n = 481) and girls (n = 485) in an urban school system in which the majority of students were African American and from low-income families. Measures of problem behavior frequency were positively correlated with each other and negatively correlated with several measures of conventional behavior. Confirmatory factor analyses replicated findings of previous studies that a single common factor underlies adolescent problem behaviors.

The plasma endorphin, prostaglandin and catecholamine profile of patients with fibrositis treated with cyclobenzaprine and placebo: a 5-month study

During a 5 month, double blind crossover study of the clinical effect of cyclobenzaprine on 7 patients with fibrositis, weekly measurements were done of plasma beta-endorphin (endorphin, prostaglandin E (PGE) and catecholamines). Endorphin levels were normal but varied with tender point tenderness. Mean plasma dopamine and PGE were elevated. Norepinephrine was normal to very high while epinephrine levels were continuously low to normal. We conclude that patients with fibrositis have a neurotransmitter plasma profile like other chronic pain states having stress and increased vasomotor activity with the possible exception of having low circulating epinephrine. This disparity may mark a failure of central nervous system pain modulation in fibrositis.

Use of adjustable sutures: a helpful modification

Adjustable suture surgery helps achieve visual axis alignment in special cases. We describe a modification of adjustable suture surgery that provides better patient comfort and easier assessment of the muscle function at the time of adjustment. These beneficial features are achieved by using the cul-de-sac approach and by delaying final adjustment up to one week postoperatively. We review our experience involving 52 cases and discuss the surgical methods and reasoning behind delayed suture adjustment through the cul-de-sac approach.

Coronoid process hyperplasia causing restricted opening and facial asymmetry

A case of coronoid process hyperplasia is presented. The primary presenting complaint and clinical feature was restriction of opening, although there was marked facial asymmetry in the area of the right zygoma. Presurgical documentation of this anatomic variation by routine radiography and computed tomography with sagittal reconstruction is presented.

Computed tomographic features in optic neuritis

A computed tomography scan obtained in two patients with monocular visual loss showed diffuse enlargement and enhancement of the intraorbital portion of the involved optic nerve. Although these tomographic features were initially interpreted as an optic nerve glioma by the neuroradiologist, the ensuing clinical course established the diagnosis of optic neuritis.

EXPERIMENTS ON INSECT TRANSMISSION OF THE VIRUS OF POLIOMYELITIS

The domestic fly (Musca domestica) can carry the virus of poliomyelitis in an active state for several days upon the surface of the body and for several hours within the gastro-intestinal tract. Mosquitos (Culex pipiens, Culex sollicitans, and Culex cantator), in our experiments, have not taken up and maintained in a living state the virus from the spinal cord of monkeys. Lice (Pediculus capitis and Pediculus vestimenti) have not taken the virus out of the blood of monkeys or maintained it in a living state. The bedbug (Cimex lectularius) has taken the virus with the blood from infected monkeys and maintained it in a living state within the body for a period of seven days.