Health Disparities in Kidney Failure Among Patients With Autosomal Dominant Polycystic Kidney Disease: A Cross-Sectional Study.

Rationale & Objective: Understanding potential differences in patterns of kidney failure among patients with autosomal dominant polycystic kidney disease (ADPKD) may provide insights into improving disease management. We sought to characterize patients with ADPKD and kidney failure across different race/ethnicities. Study Design: Cross-sectional study. Setting & Participants: Kaiser Permanente Southern California members diagnosed with ADPKD between January1, 2002, and December 31, 2018. Exposure: ADPKD. Outcome: Kidney failure, dialysis, or receipt of kidney transplant. Analytical Approach: Differences in characteristics by race/ethnicity were assessed using analysis of variance F test and χ2 test. To compare the range and distribution of the average age at onset of kidney failure by race/ethnicity and sex, we used box plots and confidence intervals. Multivariable logistic regression was used to estimate OR for kidney transplant. Results: Among 3,677 ADPKD patients, 1,027 (27.3%) had kidney failure. The kidney failure cohort was comprised of Black (n=138; 30.7%), White (n=496; 30.6%), Hispanic (n=306; 24.7%), and Asian (n=87; 23.6%) patients. Hispanic patients had the youngest mean age of kidney failure onset (50 years) compared to Black (56 years) and White (57 years) patients. Black (44.2%; OR, 0.72) and Hispanic (49.7%; OR, 0.65) patients had lower rates of kidney transplantation compared to White (53.8%) patients. Preemptive kidney transplantations occurred in 15.0% of patients. Limitations: Retrospective study design and possible misclassification of ADPKD cases. Kidney function calculations were based on equations incorporating race, potentially overestimating kidney function in African Americans. The study was conducted within a single, integrated health care system in 1 geographic region and may not be generalizable to all ADPKD patients. Conclusions: Among a large diverse ADPKD population, we observed racial/ethnic differences in rates of kidney failure, age of kidney failure onset, and rates of kidney transplantation. Our real-world ADPKD cohort provides insight into racial/ethnic variation in clinical features of disease and potential disparities in care, which may affect ADPKD outcomes.

A noncontiguous 2-level spinal injury in a young female driver due to a 3-point seat belt restraint.

OBJECTIVES: The purpose of this case is to describe noncontiguous fracture and dislocations of the thoracolumbosacral spine in a 23-year-old female driver with a 3-point seat belt restraint. CLINICAL FEATURES: A 23-year-old woman presented to us after a motor vehicle accident while driving with a 3-point seat belt restraint. She was neurologically intact except for loss of motor function in the distribution of the L5 nerve root in the right lower limb. Computed tomography and magnetic resonance imaging showed fracture and dislocation of T3 with considerable retrolisthesis and complete anterolisthesis of L5 over the sacrum. INTERVENTION AND OUTCOME: Both fractures were reduced and fixed with bone graft and instrumentation. She was discharged a month later without any further neurologic deterioration. CONCLUSIONS: To our knowledge, this case is the first report in the literature of a seat belt safety restraint causing 2 noncontiguous fracture dislocations of the spine. Although the consensus is that seat belts can prevent most spine injuries, this case shows that the seat belt can be a contributor to spine injury. It shows that the shoulder-lap restraint can act as 2 fulcrums at the upper and lower bands causing 2 separate fracture dislocations. A thorough radiologic evaluation of the spine with respect to the clinical findings is mandatory in seat belt-restrained road traffic accidents cases.

Spontaneous cervical epidural hematoma masquerading as an abscess on magnetic resonance imaging scan.

OBJECTIVE: The aims of the study are to describe a case of spontaneous spinal epidural hematoma (SSEH) without any predisposing factors and magnetic resonance imaging (MRI) features of epidural abscess and to highlight the importance of high clinical suspicion. CLINICAL FEATURES: A 75-year-old male presented to the emergency department after a severe neck pain. He progressively showed sensory and upper motor signs on the left side of the body. The MRI scans were suggestive of cervical epidural abscess with peripheral enhancement of the lesion. INTERVENTIONS AND OUTCOMES: He underwent a multiple level (C3-T1) laminectomy when he was found to have an SSEH. There has been no history of trauma or other predisposing factor, and presence of arteriovenous malformation was ruled out by MR angiography. CONCLUSIONS: The MRI features of SSEH may be misleading and mimic other spinal lesions such as abscess. Presence of tapering superior and inferior margins, spotty Gadolinium enhancement in the mass, along with abrupt clinical onset of pain and neurologic deficit, should raise the suspicion toward epidural hematoma. Enhancement in the hyperacute stage of the hematoma itself might indicate continued bleeding and, in the case of deteriorating neurologic status, will necessitate decompression.

A comparison of the torsional stiffness of the lumbar spine in flexion and extension.

OBJECTIVE: The main mechanism of injury to the spine is torsion especially when coupled with compression. In this study, the in vitro torsional stiffness of the lumbar spine segments is compared in flexion and extension positions by cyclic and failure testing. METHODS: Fifteen lumbar spines were sectioned from fresh cadavers into 15 L2/3 and 15 L45 motion segments. Each vertebral segment was then potted superiorly and inferiorly in polymethylmethacrylate, effectively creating a bone-disk-bone construct. The potted spinal segments were mounted in a mechanical testing system, preloaded in compression to 300 N, and axially rotated to 3 degrees in both directions at a load rate of 1 degrees /s. This was done over 3 cycles for each motion segment in the flexion and extension positions. Each specimen was then tested to torsional failure in either flexion or extension. Stiffness, torque, and energy were determined from cyclic and failure testing. RESULTS: The results showed that in all cases of cyclic testing, the higher segment extension resulted in higher torsional stiffness. In relative extension, the lumbar specimens were stiffer, generated higher torque values, and generally absorbed more energy than the relative flexion condition. There were no differences found in loading direction or failure testing. CONCLUSIONS: Increasing the effective torsional stiffness of the lumbar spine in extension could provide a protective mechanism against interverbral disk injury. Restoration of segmental extension through increasing the lumbar lordosis may decrease the strain and reinjury of the joints, which can help reduce the extent of pain in the lumbar spine.

Bilateral isthmic L3 spondylolisthesis in an adult female.

OBJECTIVE: The purpose of this study is to describe an incidental finding of bilateral isthmic L3 spondylolysis in an adult female. CLINICAL FEATURES: A 26-year-old woman with sickle cell anemia was involved in a motor vehicle accident. Lumbar radiographs were reported normal. Computed tomography scan showed bilateral L3 spondylolysis of the pars interarticularis. INTERVENTIONS AND OUTCOMES: On the basis of the normal results of physical and neurologic examinations, the spondylolysis was considered to be an incidental finding. CONCLUSIONS: L3 spondylolysis is described very rarely in the literature. According to the unique features of L3 in the lumbar spine, which include its relatively horizontal position and its equal anterior and posterior diameters, we suggest that mechanical shearing forces may be less effective in causing spondylolysis in this area. This case is more suggestive of congenital and genetic causes as the contributing factors of spondylolysis.