Browsing by Subject "Surgery"

Background. The confluence of a capacity-exceeding disease burden and persistent resource shortages have resulted in traumatic brain injury’s (TBI) devastating impact in low and middle income countries (LMIC). Lifesaving care for TBI depends on accurate and timely decision making within the hospital. As result of technology and highly skilled provider shortages, treatment delays are common in low resource settings. This reality demands a low cost, scalable and accurate alternative to support decision making. Decision support tools leveraging the accuracy of modern prognostic modeling techniques represents one possible solution. This thesis is a collation of research dedicated to the advancement of TBI decision support technology in low resource settings. Methods. The study location included three national and referral hospitals in Uganda and Tanzania. We performed a survival analysis, externally validated existing TBI prognostic models, developed our own prognostic model, and performed a feasibility study for TBI decision support tools in an LMIC. Results. The survival analysis revealed a greater surgical benefit for mild and moderate head injuries compared to severe injuries. However, severe injury patients experienced a higher surgery rate than mild and moderate injuries. We developed a prognostic model using machine learning with a good level of accuracy. This model outperformed existing TBI models in regards to discrimination but not calibration. Our feasibility study captured the need for improved prognostication of TBI patients in the hospital. Conclusions. This pioneering work has provided a foundation for further investigation and implementation of TBI decision support technologies in low resource settings.

Laser scalpels are utilized across a variety of invasive and non-invasive surgical procedures due to their precision and non-contact nature. Meanwhile, robotic and robotic-assisted surgeries are becoming more prevalent with the promise of improving surgical outcomes through increased precision, reduced operating times, and minimally invasive procedures. This dissertation presents methods and devices developed to enable assistive robotic laser surgery, with the goal of realizing the surgical benefits of both and ultimately improving surgical outcomes for patients.

The device is first used to demonstrate targeted soft tissue resection in porcine brain in an open-loop fashion. This device, coined the "TumorCNC" combines 3D scanning capabilities with a steerable surgical laser. Results show high variance around target cut depths which motivats the need for a closed-loop feedback and control as well as characterization of laser-tissue interactions for predictive modeling.

To begin to address the technical difficulties of closed-loop ablation, a model-based approach is taken. A soft tissue ablation simulator is developed and used in conjunction with an optimization routine to select parameters which maximize the total resection of target tissue while minimizing the damage to surrounding tissue. The optimization is performed using genetic algorithms. The simulator predicts the ablative properties of tissue from an interrogation cut for tuning and simulates the removal of a tumorous tissue embedded on the surface of healthy tissue using a laser scalpel. This demonstrates the ability to control depth and smoothness of cut using genetic algorithms to optimize the ablation parameters and cutting path. The laser power level, cutting rate and spacing between cuts are optimized over multiple surface cuts to achieve the desired resection volumes.

Noting that the modeling approached developed is applicable to other laser treatments requiring uniformity of laser energy deposition, a study of superficial region ablation is performed for applications in dermatology. The TumorCNC is now outfitted with an RGB-D camera. To accurately ablate targets chosen from the color image, a 3D extrinsic calibration method between the RGB-D camera frame and the laser coordinate system is implemented. The accuracy of the calibration method is tested on phantoms with planar and cylindrical surfaces. Positive error and negative error, as defined as undershooting and overshooting over the target area, are reported for each test. For 60 total test cases, the root-mean-square of the positive and negative error in both planar and cylindrical phantoms is less than 1.0mm, with a maximum absolute error less than 2.0mm. This work demonstrates the feasibility of automated laser therapy with surgeon oversight via our sensor system.

As a demonstration of the culmination of these techniques, a closed-loop, adaptive online estimation of ablative properties for soft tissue laser resection of tumors is demonstrated. First, a laser photoablation feature is created in an agarose based tissue phantom using a robotic laser photoablation device equipped with a carbon dioxide laser. Second, the device measures the surface profile of the ablated feature for analysis. Genetic algorithms in conjunction with the photoablation simulator based on the steady-state photoablation model are used to estimate the photoablation enthalpy, density, and ablative radiant threshold of the tissue phantom. The parameters and model are validated through comparison of predicted and measured surface ablations at varying depths. This approach proved effective for predicting the resulting surface profiles for small cut depths (<= 2mm) and generating laser cut paths to reach a desired depth of cut for a large surface area. This work is enabling of closed-loop resection of tissue in robotic laser surgery.

Purpose:

The overall purpose of this study was a comparison of radiation exposure for patients and staff during intra-operative imaging for orthopedic lumbar spine surgery. In order to achieve this, we: (1) Characterized each x-ray machine for physics performance, (2) Measured occupational radiation exposure inside the surgical suite for multiple intra-operative imaging devices utilizing currently in place clinical protocols for abdominal/spinal imaging, and (3) Measured specific organ doses for a phantom of three different Body Mass Indices (BMI) for each machine. We also compared the dose changes relative to changes in BMI as well as surgical image quality changes relative to BMI. This served as the majority of the first phase of a two phase project. The purpose of the second phase of the project will be to optimize scan parameters for surgical hardware placement in terms of image quality and organ dose for the devices that allow for modifications of scanner settings.

Materials and Methods:

(1) X-Ray quality control meters were used to verify particular beam characteristics and additional information was calculated from the beam data. Both a small volume ionization chamber as well as Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) dosimeters were used to validate linear response of new design X-Ray tubes. (2) Both handheld ionization chamber survey meters as well as Geiger-Muller based personal dose meters were used to measure stray radiation for room surveys in locations representative of typical radiation worker positions during intra-operative imaging. (3) MOSFET dosimeters were placed in an adult male anthropomorphic phantom representing a normal BMI. 20 MOSFETs were used in nine organs with two small volume ion chambers used for skin surface dosimetry. Two additional layers of adipose equivalent material were progressively added to the phantom to represent BMI values of overweight and obese.

Results:

(1) The maximum tube potential, half value layer (HVL), effective energy, and soft tissue f-factor for each machine is as follows: IMRIS VISIUS iCT: 118.4 kVp, 7.66 mm Al, 53.64 keV, and 0.934 cGy/R; Mobis Airo: 122.3 kVp, 7.21 mm Al, 51.31 keV, and 0.925 cGy/R; Siemens ARCADIS Orbic 3D: 83 kVp, 7.12 mm Al, 32.76 keV, and 0.914 cGy/R; GE OEC 9900 Elite: 75 kVp, 4.25 mm Al, 46.6 keV, and 0.920 cGy/R. (2) The highest exposure rates measured during clinically implemented protocols for each scanner are as follows: IMRIS VISIUS iCT: 800 mR/hr; Mobis Airo: 6.47 R/hr; Siemens ARCADIS Orbic 3D: 26.4 mR/hr. (3) The effective dose per scan of each device for a full lumbar spine scan are as follows, for normal, overweight, and obese BMI, respectively: IMRIS VISIUS iCT: 12.00 ± 0.30 mSv, 15.91 ± 0.75 mSv, and 23.23 ± 0.55 mSv; Mobius Airo: 5.90 ± 0.25 mSv, 4.97 ± 0.12 mSv, and 3.44 ± 0.21 mSv; Siemens ARCADIS Orbic 3D: 0.30 ± 0.03 mSv, 0.39 ± 0.02 mSv, and 0.28 ± 0.03 mSv; GE OEC 9900 Elite: 0.44 mSv, 0.77 mSv, and 1.14 mSv.

Conclusion:

(1) The IMRIS VISIUS iCT i-Fluoro capable CT scanner and Mobius Airo mobile CT scanner have similar beam characteristics with significantly different tube parameter modulation protocols. Siemens ARCADIS Orbic 3D and GE OEC 9900 offer comparable beam characteristics but different imaging methods. All scanners performed within factory specifications. (2) The IMRIS VISIUS iCT should not be used in i-Fluoro mode for surgical procedures active during scanning due to the 1.42 cGy/s point dose rate in the beam field. The high exposure rate from the Mobius Airo is offset by short scan times and can be mitigated by ensuring enforcement of currently established radiation protection regulations and policies. Minimal stray radiation is measured from the Siemens ARCADIS Orbic 3D. (3) The differences in tube modulation of the CT scanners means the Mobius Airo offers a significantly reduced effective dose with increasing patient BMI over the IMRIS VISIUS iCT. Effective dose from the CT scanners varies as much as one to two orders of magnitude higher than the C Arms, but the Siemens ARCADIS Orbic 3D offers unusable image quality for patients with higher than normal BMI. Based off of physician reported usable surgical image quality of Mobius Airo, this device is recommended for continued integration and implementation during routine surgical procedures for patients of all BMI in orthopedic lumbar spine surgery.

Background: Robeson County, North Carolina was ranked as the least healthy county in the state, in 2020. In Robeson, accessing surgical care is a health challenge, and two known risk factors are its rural location and high proportion of racial minority groups. Applying the three-delays model, the aim of this study was to identify and assess the perceived barriers to surgical care. Methods: To obtain a diverse perspective of how access to surgical care in Robeson County is perceived, interviews were conducted with surgical patients, surgical providers, and community leaders. Duke healthcare personnel, who work in Robeson County, assisted with identifying appropriate stakeholders and surgical patients to interview initially. Additional interviewees were identified through snowball sampling, until saturation was reached. Two researchers independently examined and categorized the responses using the constant comparative method, categorizing quotes from participants in an iterative fashion to identify recurring themes. Results: A total of eleven participants were interviewed (2 nurses, 7 patients, and 2 community leaders). Themes identified included: comfort level with the health system, transportation, logistics of the health system, health system capacity, alternative medicine, community beliefs, county’s historical and cultural context, financing, and suggestions from the participants. Conclusions: This preliminary study suggests that along with Robeson’s rural geography and high proportion of minority groups, the county’s historical and cultural context, the stigmatization of surgical diseases, and the knowledge gap in resource availability also contribute to barriers to accessing surgical care in the county.

Background

Methods

Results

Conclusions

It is well understood that loss of motion following spinal fusion increases strain in the adjacent motion segments. However, it is unclear if to date, studies on cervical spine biomechanics can be affected by the role of coupled motions in the lumbar spine. Accordingly, we investigated the biomechanics of the cervical spine following cervical fusion and lumbar fusion during simulated whiplash.

A validated whole-human finite element model was used to investigate whiplash injury. The cervical spine before and after spinal fusion was subjected to simulated whiplash exposure in accordance with Euro NCAP testing guidelines, and the strains in the anterior longitudinal ligaments of the adjacent motion segments were computed.

In the models of cervical arthrodesis, peak ALL strains were higher in the motion segments adjacent to the level of fusion, and strains directly increased with longer fusions. The mean strain increase in the motion segment immediately adjacent to the site of fusion from C2-C3 through C5-C6 was 26.1% and 50.8% following single- and two-level cervical fusion (p=0.03). On average, peak strains experienced in a lumbar-fused spine were 1.0% less than those seen in a healthy spine (p=0.61). The C3-C4 motion segment had disproportionately high increases in strain following cervical fusion. The C6-C7 motion segment experienced high absolute strain under all tested conditions but the increase in strain following fusion was very small. This study provides support for both the hypothesis that adjacent segment disease is associated with post-arthrodesis biomechanical influences and the hypothesis that adjacent segment disease is a result of natural history, and inherent structures at risk.

Background: Over 1.7 billion children and adolescents around the world lack access to safe and affordable surgical care, mostly in low- and middle-income countries (LMICs), where children and adolescents can account for up to half of a country’s population. Yet, the burden of surgical needs for children in Tanzania is still poorly defined. The aim of this study is to assess the epidemiology and outcomes of pediatric surgical procedures performed over one year at the Kilimanjaro Christian Medical Centre, Moshi, Tanzania.Methods: We reviewed the medical and surgical records of all children (< 16 years of age) who underwent surgery between January 1st, 2022 and December 31st, 2022 at the Kilimanjaro Christian Medical Centre. Descriptive statistics were used to assess demographic and clinical characteristics. Geospatial mapping tools were used to visualize the distribution of the patient’s district of origin. Results: We collected data on 2031 children, 59.8% (n = 1215) of whom were male, and more than half were between 1 and 5 years old (58.6%, [n = 1191]). In terms of procedure type, half of the procedures were tonsillectomies/adenoidectomies (51.1%), followed by laparotomies (3.4%), and ventriculoperitoneal shunts (3.2%). We identified 33 deaths prior to discharge. Children from uninsured families and those under one year old were more likely to have traveled longer, visited another health facility, and required an emergency procedure compared to children from insured families and other age groups. Conclusion: Being a child who is under one year old and from an uninsured family is associated with more urgent procedures and poorer outcomes, highlighting disparities in access to surgery for children in Northern Tanzania. Resource mobilization to provide financial protection for families who seek surgical care and health system strengthening at lower-level hospitals are crucial to addressing inequitable and unaffordable access to surgical care and improving health outcomes for children across Tanzania.

Background: Traumatic Brain Injury (TBI) is disproportionally concentrated in low- and middle-income countries (LMICs), with the odds of dying from TBI in Uganda more than 4 times higher than in high income countries (HICs). The objectives of this study are to describe the quality of care and determine risk factors predictive of poor outcomes for TBI patients presenting to Mulago National Referral Hospital (MNRH), Kampala Uganda.

Methods: We used a prospective neurosurgical registry based on Research Electronic Data Capture (REDCap) to systematically collect variables spanning 8 categories. Univariate and multivariate analysis were conducted to determine significant predictors of mortality.

Results: 563 TBI patients were enrolled from 1 June – 30 November 2016. 102 patients (18%) received surgery, 29 patients (5.1%) intended for surgery failed to receive it, and 251 patients (45%) received non-operative management. Overall mortality was 9.6%, which ranged from 4.7% for mild and moderate TBI to 55% for severe TBI patients with GCS 3-5. Within each TBI severity category (mild, moderate, severe GCS 6-8, severe GCS 3-5), mortality differed by management pathway. The variables predictive of mortality were: moderate to severe TBI (GCS 9-12, GCS 6-8, and GCS 3-5), more than one intracranial bleed, failure to receive surgery, high dependency unit admission, ventilator support outside of surgery, and hospital arrival delayed by more than 4 hours.

Conclusions: The overall mortality rate of 9.6% in Uganda for TBI is high, and likely underestimates the true TBI mortality. Furthermore, the wide-ranging mortality (3-82%), high ICU fatality, and negative impact of care delays suggest shortcomings with the current triaging practices. Lack of surgical intervention when needed was highly predictive of mortality in TBI patients. Further research into the determinants of surgical interventions, quality of step-up care, and prolonged care delays are needed to better understand the complex interplay of variables that affect patient outcome. These insights guide the development of future interventions and resource allocation to improve patient outcomes.

Background: Globally, there is often a gap between medical need and access to care, and this is particularly true for surgical care for children. In Guatemala, for instance, families frequently pursue care outside of the government health system. Using a structured anthropologic approach, we sought to explore the barriers to surgical care for children in Guatemala, suspecting both financial and cultural barriers were the primary obstacles families had to face.

Study design: Twenty-nine parents/guardians of children receiving surgical care at two non-governmental organizations (NGOs) in Guatemala and 7 health care providers participated in semi-structured interviews to explore what they believed to be the impediments to care. Transcripts were analyzed using a grounded theory approach. Current models for barriers to care were critiqued and a novel Framework for Barriers to Pediatric Surgery in Guatemala (FBPSG) was developed, which highlights both the existence, and centrality, of fear and mistrust in families' experience.

Results: Families and providers identified financial costs, geography, and systems limitations as the primary barriers to care. Mistrust and fear were also voiced. In addition, health literacy and cultural issues were also thought to be relevant by providers.

Conclusions: Due to biases inherent in this sample, parents/guardians did not necessarily report the same perceived barriers as healthcare providers - e.g., education/health literacy and language - and may have represented a "best case" scenario compared to more disadvantaged populations in this specific Central American context. Nonetheless, financial concerns were some of the most salient barriers for families seeking pediatric surgical care in Guatemala, with systems limitations (waiting time) and geographic factors (distance/transit) also being highlighted. Fear and mistrust were found to be deeper barriers to care and warrant reevaluation of organizational heuristics to date. NGOs can address these worries by working with individuals and organizations already known by and trusted in target communities and by providing good quality medical treatment and interpersonal care.

Background/ObjectivesAfrica has only 1% of the global neurosurgery workforce, despite having 14% of the global population and 15% of the global neurosurgical disease burden. Also, neurosurgical training is hampered by paucity of training institutions, dearth of training faculty, and deficiency of optimal training resources. The study appraises the current specialist neurosurgical workforce in Africa, evaluates the major neurosurgery training programs, and projects the 2030 workforce capacity using current growth trends. Methods The study involved systematic and gray literature search, with quantitative analysis of retrospective data on the neurosurgery workforce, qualitative evaluation of the major neurosurgery training programs for their strength, weaknesses, opportunities, and threats, and projection modeling of the workforce capacity up to year 2030. Results 1,974 neurosurgeons serve 1.3 billion people (density 0.15/100,000; ratio 1:678,740), in Africa, with the majority (1,271; 64.39%) in North Africa. There are 106 specialist neurosurgery training institutions in 26 African countries, with North Africa having 52 (49.05%) of the training centers. Training is heterogenous, with the major programs being the West African College of Surgeons (WACS) - 24 centers across 7 countries, and the College of Surgeons of East, Central and Southern Africa (COSECSA) - 17 centers in 8 countries. At the current linear growth rate of 74.2 neurosurgeons/year or exponential growth rate of 6.81% per annum, Africa will have 2,716 - 3,813 neurosurgeons by 2030, with a deficit of 4,795 - 11,953 neurosurgeons. The continent requires a scale-up of its linear growth rate to 663.4 - 1269.5 neurosurgeons/year, or exponential growth rate to 15.87% - 22.21% per annum to meet its needs. While North African countries will likely meet their 2030 workforce requirements, sub-Saharan African countries will have significant workforce deficits. Conclusion Despite a recent surge in neurosurgery residency training, the current state of Africa’s neurosurgery workforce is dire, and many countries will be unable to meet their workforce requirements by 2030 at current growth trends. A significant scale-up of the neurosurgery workforce is required in order to meet these targets.

Purpose of review

Recent findings

Summary

Background: A staggering 5 billion people worldwide lack access to safe and affordable surgery, and surgical conditions contribute to up to 32% of the global disease burden. However, precise data on the burden of surgical conditions is lacking, particularly for children. This study aims to measure the burden of pediatric surgical conditions in Somaliland using a community-based, household, nationwide survey as well as a national hospital survey to identify the types and volume of pediatric surgical care.

Methods: We surveyed 1450 children, from 839 families, through national community-based sampling using the Surgeons OverSeas Assessment of Surgical Need (SOSAS) survey to identify the prevalence of surgical conditions. We also performed a hospital capacity survey at 15 hospitals in Somaliland, with surgical records reviewed over a 1-year time frame to identify pediatric surgical procedures performed.

Results: Using a community survey, we identified 226 surgical conditions in 191 children, yielding a surgical condition prevalence of 13.7% in the pediatric population. Only 55 of 226 conditions were treated with a surgical procedure. The most common conditions reported were congenital deformities (34.4%) and wound related injuries (23.8%). Using a hospital survey, we identified 1255 pediatric surgical procedures performed nationally over 1 year. We found that 56.7% procedures were in performed in boys and 79.8% were done at private hospitals. The most common surgical diagnoses were tonsillitis, trauma/wound/snake bite, and hydrocephalus.

Conclusions: Between 91,500 – 209,000 children in Somaliland have an unmet need for pediatric surgery, highlighting the high burden of surgical disease in the country. The estimated number of performed surgical procedures represents a small fraction of the burden of pediatric surgical conditions, highlighting the need for expansion of infrastructure, resources, and workforce to provide needed surgical care.

An estimated 234.2 million major surgical procedures are performed annually worldwide, yet the wealthiest third of the world's population receives 73.6% while the world's poorest third receives only 3.5%. Approximately one-third of the global population has no access to basic surgical care. Knowing that large unmet surgical need in a community can lead to high morbidity and mortality in the population, the purpose of this novel study was to assess the level of surgical conditions in rural Gadchiroli, India as well as to conduct a quantitative assessment of the barriers to surgical care. In this retrospective, cross-sectional needs assessment, a study-specific survey was administered in a clinic-based setting. Of the 500 participants, 141 (28.2%) reported surgical conditions, for a total of 175 surgical cases, in the preceding two years. The conditions with the highest prevalence were hydrocele, anorectal processes, dysfunctional uterine bleeding, cataracts, appendicitis, and spondylosis with neurologic claudication. Assessment of the conditions by a healthcare provider occurred in 133 (76.6%) of the cases of which only 32 (24.1%) reported having undergone surgery during the two year period. Overall, in this population, the burden of surgical disease is higher than previously expected and while willingness to undergo surgery is high, the completion rate is quite low. Certain factors appear to predict difficulty in seeking or receiving surgical care, including lost wages (p=0.027), the amount of time that family members need to stay in the hospital to help (p=0.038), and time away from work (p=0.045). Targeting these factors is a first step towards addressing the unmet surgical needs in this rural community.

Background: Globally, 5 billion people lack timely access to safe and affordable surgical care, with over a fifth of them living in India. Solving India’s surgical access issues can have high returns on investment. While healthcare access and unaffordability problems are well-known in India particularly among its rural people, research on surgical care is scant. This study attempts to fill the research gap through high-resolution nationwide estimates that have direct implications for India’s national surgical plan. Methods: Secondary data analysis with a diverse geospatial and statistical toolbox was used to create the national, state, and district-level estimates in four surgical care access dimensions. The four access dimensions were: timeliness (proportion of population within 2 hours of a surgical are facility), capacity (met surgical need for operative volumes), safety (proportion of post-operative surgical site infections), and affordability (proportion of surgery-seeking households facing catastrophic expenses). A novel composite index was introduced for assessing surgical access integrating the above dimensions. Distributional and spatial inequalities in access across Indian districts and states were measured to depict regions needing policy intervention. Correlations with Sustainable Development Goals (SDG) scores were computed. Validation and sensitivity analyses were conducted to check the robustness of the findings. Results: Timely access to surgical care was achieved by > 99% of the rural population, but only 6.81% of surgical need was met. SSI proportion was 0.19% and 60.99% of surgery-seeking households faced catastrophic health expenditure. Heterogeneities in these dimensions were observed at state and district-levels. Significant rural-urban differences were observed in surgical care access dimensions and other considered surgical care variables. The Zadey-Vissoci Access to Surgical Care Index (ZV-ASCI) depicted limited access across several states and districts. Within-state distributional inequality in ZV-ASCI was about three times that of between-states. We found limited support for spatial autocorrelations and identified the low access district clusters. For aspirational districts, whose development is high on the national agenda, ZV-ASCI was not correlated with SDG composite score. Conclusions: Our methodological workflow has high translational value for global surgery research in low-and-middle-income countries. For India, these are the first such nationwide findings that can direct the development of a National Surgical, Obstetric, and Anesthesia Plan (NSOAP). The proposed index can encourage buy-in from policymakers and raise surgical care on the global and national agenda.