Clinical spine care partnerships between high-income countries and low-and-middle-income countries: A scoping review.

BACKGROUND: Clinical collaboration between spine professionals in high-income countries (HICs) and low-and-middle-income countries (LMICs) may provide improvements in the accessibility, efficacy, and safety of global spine care. Currently, the scope and effectiveness of these collaborations remain unclear. In this review, we describe the literature on the current state of these partnerships to provide a framework for exploring future best practices. METHODS: PubMed, Embase, and Cochrane Library were queried for articles on spine-based clinical partnerships between HICs and LMICs published between 2000 and March 10, 2023. This search yielded 1528 total publications. After systematic screening, nineteen articles were included in the final review. RESULTS: All published partnerships involved direct clinical care and 13/19 included clinical training of local providers. Most of the published collaborations reviewed involved one of four major global outreach organizations with the majority of sites in Africa. Participants were primarily physicians and physicians-in-training. Only 5/19 studies reported needs assessments prior to starting their partnerships. Articles were split on evaluative focus, with some only evaluating clinical outcomes and some evaluating the nature of the partnership itself. CONCLUSIONS: Published studies on spine-focused clinical partnerships between HICs and LMICs remain scarce. Those that are published often do not report needs assessments and formal metrics to evaluate the efficacy of such partnerships. Toward improving the quality of spine care globally, we recommend an increase in the quality and quantity of published studies involving clinical collaborations between HICs and LICs, with careful attention to reporting early needs assessments and evaluation strategies.

Ultrasound Shear Wave Elastography Quantitatively Assesses Tension Changes of Supraspinous/Interspinous Ligament Complex Under Varied Loads.

BACKGROUND: Although interspinous and supraspinous ligaments of the lumbar spine are thought to contribute to spinal stability, little is known about their dynamic biomechanics. We demonstrate that shear wave elastography (SWE) offers a novel technique to noninvasively and quantitatively evaluate posterior spinous ligament complex functional loading and stiffness in different physiologic positions. METHODS: We performed SWE and measured the length of the interspinous/supraspinous ligament complex in cadaveric torsos (N = 5), isolated ligaments (N = 10), and healthy volunteers (N = 9) to obtain length and shear wave velocity measurements. For cadavers and volunteers, SWE was utilized in 2 lumbar positions: lumbar spine flexion and extension. In addition, SWE was performed on isolated ligaments undergoing uniaxial tension to correlate shear wave velocities with experienced load. RESULTS: Average shear wave velocity in cadaveric supraspinous/interspinous ligament complexes increased for lumbar levels (23%-43%) and most thoracic levels (0%-50%). This corresponded to an average increase in interspinous distance from extension to flexion for the lumbar spine (19%-63%) and thoracic spine (3%-8%). Volunteer spines also demonstrated an average increase in shear wave velocity from extension to flexion for both the lumbar spine (195% at L2-L3 to 200% at L4-L5) and thoracic spine (31% at T10-T11). There was an average increase in interspinous distance from extension to flexion for the lumbar spine (93% at L2-L3 to 127% at L4-L5) and thoracic spine (11% at T10-T11). In isolated ligaments, there was a positive correlation between applied tensile load and average shear wave velocity. CONCLUSION: This study creates a foundation to apply SWE as a noninvasive tool for assessing the mechanical stiffness of posterior ligamentous structures and has potential applications in augmenting or evaluating these ligaments in patients with spine pathology. CLINICAL RELEVANCE: The interspinous and supraspinous ligaments are critical soft tissue supports of the posterior lumbar spine. Disruption of these structures is thought to have a negative impact on spinal stability in trauma and spine deformities.

Increase in surgeons performing outpatient anterior cervical spine surgery leads to a shift in case volumes over time.

Background: Prior studies have demonstrated an increase in the performance of outpatient anterior cervical surgery. The degree to which this increase is due to volume increase per individual surgeon versus increase in individual surgeons performing outpatient cervical surgery is unknown. Methods: Patients undergoing anterior cervical discectomy and fusion (ACDF) or cervical disk arthroplasty (CDA) between 2010 and 2018 in NY state were identified. As a comparison we also evaluated trends for inpatient ACDF and CDA. Annual outpatient case volumes were calculated and defined as being high (> 20/year), intermediate (>5 and ≤ 20/year) or low (>1 and ≤ 5/year). Descriptive statistics were used to report temporal trends and Poisson regression was used to test for statistical significance. We also analyzed trends in various operative metrics by surgeon volume. Results: In 2010, there were 96 surgeons who performed outpatient ACDF or CDA on a total of 1,855 patients. In 2018, this increased to 253 surgeons performing outpatient ACDF or CDA on a total of 3,372 patients. In comparison, there were 350 surgeons performing 6,783 inpatient cases in 2010 and 376 surgeons performing 6,796 inpatient cases in 2018. The average annual outpatient case volume decreased from 18.8 (95% CI, 13.5 - 24.1) to 12.2 (95% CI, 10.0 - 14.3) surgeries per surgeon. The percentage of surgeons with a high case volume also decreased from 30.2% in 2010 to 10.7% in 2018, whereas the percentage with a low case volume increased (32.3% to 49.8%). Differences between high and low volume surgeons in operative time, length of stay and total charges widened over time. Conclusion: The increase in outpatient anterior cervical surgery appears to be primarily driven by a greater number of surgeons performing ACDF and CDA on an outpatient basis, as opposed to increased case volumes for each surgeon. In contrast, trends for inpatient anterior cervical surgery were stable.

Axial variation in flexural stiffness of plant stem segments: measurement methods and the influence of measurement uncertainty.

BACKGROUND: Flexural three-point bending tests are useful for characterizing the mechanical properties of plant stems. These tests can be performed with minimal sample preparation, thus allowing tests to be performed relatively quickly. The best-practice for such tests involves long spans with supports and load placed at nodes. This approach typically provides only one flexural stiffness measurement per specimen. However, by combining flexural tests with analytic equations, it is possible to solve for the mechanical characteristics of individual stem segments. RESULTS: A method is presented for using flexural tests to obtain estimates of flexural stiffness of individual segments. This method pairs physical test data with analytic models to obtain a system of equations. The solution of this system of equations provides values of flexural stiffness for individual stalk segments. Uncertainty in the solved values for flexural stiffness were found to be strongly dependent upon measurement errors. Row-wise scaling of the system of equations reduced the influence of measurement error. Of many possible test combinations, the most advantageous set of tests for performing these measurements were identified. Relationships between measurement uncertainty and solution uncertainty were provided for two different testing methods. CONCLUSIONS: The methods presented in this paper can be used to measure the axial variation in flexural stiffness of plant stem segments. However, care must be taken to account for the influence of measurement error as the individual segment method amplifies measurement error. An alternative method involving aggregate flexural stiffness values does not amplify measurement error, but provides lower spatial resolution.

Reassessing the labor curve in nulliparous women.

OBJECTIVES: Our purpose was to examine the pattern of labor progression in nulliparous parturients in contemporary obstetric practice. STUDY DESIGN: We extracted detailed labor data from 1329 nulliparous parturients with a term, singleton, vertex fetus of normal birth weight after spontaneous onset of labor. Cesarean deliveries were excluded. We used a repeated-measures regression with a 10th-order polynomial function to discover the average labor curve under contemporary practice. With use of an interval-censored regression with a log normal distribution, we also computed the expected time interval of the cervix to reach the next centimeter, the expected rate of cervical dilation at each phase of labor, and the duration of labor for fetal descent at various stations. RESULTS: Our average labor curve differs markedly from the Friedman curve. The cervix dilated substantially slower in the active phase. It took approximately 5.5 hours from 4 cm to 10 cm, compared with 2.5 hours under the Friedman curve. We observed no deceleration phase. Before 7 cm, no perceivable change in cervical dilation for more than 2 hour was not uncommon. The 5th percentiles of rate of cervical dilation were all below 1 cm per hour. The 95th percentile of time interval for fetal descent from station +1/3 to +2/3 was 3 hours at the second stage. CONCLUSION: Our results suggest that the pattern of labor progression in contemporary practice differs significantly from the Friedman curve. The diagnostic criteria for protraction and arrest disorders of labor may be too stringent in nulliparous women.

U.S. national trends in labor induction, 1989-1998.

OBJECTIVE: To examine the epidemiology of labor induction in the United States. STUDY DESIGN: We used U.S. natality data from 1989 to 1998 and examined the rate of labor induction by year, geographic region, maternal characteristics and pregnancy complications. RESULTS: Between 1990 and 1998, the rate of labor induction increased from 9.5% to 19.4% of all births nationwide. However, the induction rate varied widely by state. White race, higher education and early initiation of prenatal care were associated with a higher rate of induction. For all gestational ages, a significantly increased induction rate occurred during the study period. The increase for clinically indicated induction was significantly slower than the overall increase, suggesting that elective induction has risen much more rapidly. CONCLUSION: The rate of induction of labor more than doubled in the U.S. nationwide in the decade from 1989 to 1998. The increased use of labor induction may be attributable to both clinically indicated and elective induction.

Risk factors for early cytologic abnormalities after loop electrosurgical excision procedure.

OBJECTIVE: To evaluate risk factors for early cytologic abnormalities and recurrent cervical dysplasia after loop electrosurgical excision procedure (LEEP). METHODS: A retrospective analysis was performed of all pathology records for LEEPs performed at our institution from January 1996 through July 1998. Follow-up cytology from 2 through 12 months after LEEP was reviewed. Patients with abnormal cytology were referred for further colposcopic evaluation. Statistical analysis using chi2 test for trend, proportional hazards model test, Fisher exact tests, and life table analysis were performed to identify risk factors for early cytologic abnormalities after LEEP and to determine relative risk of recurrent dysplasia. RESULTS: A total of 298 women underwent LEEP during the study period, and 29% of these had cytologic abnormalities after LEEP. Grade of dysplasia, ectocervical marginal status, endocervical marginal status, and glandular involvement with dysplasia were not found to be independent risk factors for early cytologic abnormalities. However, when risk factors were analyzed cumulatively, the abnormal cytology rate increased from 24% with no risk factors to 67% with three risk factors present (P =.037). Of patients with abnormal cytology after LEEP, 40% developed subsequent dysplasia, and the mean time to diagnosis was approximately 6 months. The relative risk of subsequent dysplasia ranged from a 20% increase to twice the risk if post-LEEP cytology was low-grade squamous intraepithelial lesion or high-grade squamous intraepithelial lesion, respectively. CONCLUSION: Based on these results, consideration should be given for early colposcopic examination of patients who have evidence of marginal involvement or endocervical glandular involvement with dysplasia. These patients are at increased risk for abnormal cytology and recurrent dysplasia. This initial visit should occur at 6 months, as the mean time to recurrence of dysplasia was 6.5 months.