Minimally Invasive Tubular Lumbar Discectomy Versus Conventional Open Lumbar Discectomy: An Observational Study From the Canadian Spine Outcomes and Research Network.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: We evaluated the effectiveness of minimally invasive (MIS) tubular discectomy in comparison to conventional open surgery among patients enrolled in the Canadian Spine Outcomes and Research Network (CSORN). METHODS: We performed an observational analysis of data that was prospectively collected. We implemented Minimum Clinically Important Differences (MCIDs), and we adjusted for potential confounders with multiple logistic regression. Adverse events were collected according to the Spinal Adverse Events Severity (SAVES) protocol. RESULTS: Three hundred thirty-nine (62%) patients underwent MIS tubular discectomy and 211 (38%) underwent conventional open discectomy. There were no significant differences between groups for improvement of leg pain and disability, but the MIS technique was associated with reduced odds of achieving the MCID for back pain (OR 0.66, 95% CI 0.44 to 0.99, P < 0.05). We identified statistically significant differences in favor of MIS for each of operating time (MIS mean (SD) 72.2 minutes (30.0) vs open 93.5 (40.9)), estimated blood loss (MIS 37.9 mL (36.7) vs open 76.8 (71.4)), length of stay in hospital (MIS 73% same-day discharge vs open 40%), rates of incidental durotomy (MIS 4% vs open 8%), and wound-related complications (MIS 3% vs open 9%); but not for overall rates of reoperation. CONCLUSIONS: Open and MIS techniques yielded similar improvements of leg pain and disability at up to 12 months of follow-up, but MIS patients were less likely to experience improvement of associated back pain. Small differences favored MIS for operating time, blood loss, and adverse events but may have limited clinical importance.

Morphometric analysis of distal interphalangeal joint and implications for arthrodesis with a headless compression screw.

Using radiographs of a cross section of patients, measurements of phalanges were done to aid in surgical planning for distal interphalangeal joint (DIPJ) arthrodesis using a headless compression screw. Measurements were performed of the distal and middle phalanx of all fingers and the proximal and distal phalanx of the thumb. Three independent reviewers measured 50 patients. The average measurements (in mm) of anteroposterior (AP) dimensions were as follows: for the thumb P1 and P2: 5.7 and 5.5, lateral 4.2 and 3.5; for the index P2 and P3 AP: 4.2 and 3.3, lateral 2.1 and 1.8; for the long P2 and P3 AP: 4.5 and 3.5, lateral 2.2 and 1.8; for the ring P2 and P3 AP: 4.3 and 3.1, lateral 1.8 and 1.7; and for the small P2 and P3 AP: 3.7 and 2.2, lateral 1.8 and 1.5. Careful surgical planning by measuring the involved digit and knowledge of screw size is paramount to avoid complications from DIPJ arthrodesis with a compression screw.

Radiographic results of fully uncemented trabecular metal reverse shoulder system at 1 and 2 years' follow-up.

BACKGROUND: The purpose of this study was to assess the short-term radiographic outcome of a fully uncemented reverse total shoulder arthroplasty (RTSA) system. MATERIALS AND METHODS: We reviewed the radiographs of 98 consecutive patients undergoing uncemented RTSA. All patients had a standardized series of radiographs taken at 2 weeks, 1 year, and 2 years postoperatively. Humeral stems were evaluated for radiolucent lines by zone and component subsidence. Evaluation for scapular notching and radiolucency surrounding the baseplate implant within the glenoid vault was also performed. RESULTS: At 1 year, 93.9% of humeral stems had no lucent lines and 6.1% had less than 2 mm of lucency. Of the scapulae, 76.6% showed no evidence of notching, 21.4% had type 1 scapular notching, and 2.0% had type 2 notching at 1 year. At 2 years, 89.5% of humeral stem components had no lucent lines and 10.5% had less than 2 mm of lucency. Fifty-seven percent of scapulae had no notching, 34.2% had type 1 notching, 5.3% had type 2 notching, and 2.6% had type 3 notching. No stems had lucency in more than 1 zone or lucency ≥ 2 mm; 9.2% had subsidence of 2 mm or less. No glenoid components had any lucency around the baseplate or screws. CONCLUSIONS: Cementless trabecular metal porous-coated implants for RTSA are associated with secure glenoid fixation and minimal radiographic evidence of humeral stem loosening or subsidence at short-term follow-up. The rates of scapular notching found in our study are comparable to previous studies and did not affect implant stability.

Scattering of a partially-coherent wave from a material circular cylinder.

The case of a partially-coherent wave scattered from a material circular cylinder is investigated. Expressions for the TMz and TEz scattered-field cross-spectral density functions are derived by utilizing the plane-wave spectrum representation of electromagnetic fields and cylindrical wave transformations. From the analytical scattered-field cross-spectral density functions, the mean scattering widths are derived and subsequently validated via comparison with those computed from Method of Moments Monte Carlo simulations. The analytical relations as well as the simulation results are discussed and physically interpreted. Key insights are noted and subsequently analyzed.