Honors & Awards
Fulbright Research Scholarship, U.S. Department of State (2010)
Fall Courses Travel Award, Association of Academic Surgery (AAS) (2017)
Resident Research Award, American College of Surgeons (ACS) (2017-2019)
Advanced Residency Training at Stanford (ARTS) Program award, Ph.D. training funding, Stanford University (2017-2020)
Current Clinical Interests
- Surgical Oncology
Michael Longaker, Longaker Laboratory (7/1/2017)
Surgical Site Infections after Inguinal Hernia Repairs Performed in Low and Middle Human Development Index Countries: A Systematic Review.
Inguinal hernias are a common disorder in low- and middle-human development index countries (LMHDICs). Poor access to surgical care and lack of patient awareness often lead to delayed presentations of incarcerated or strangulated hernias and their associated morbidities. There is a scarcity of data on the baseline incidence of surgical site infections (SSIs) after hernia repair procedures in LMHDICs.We performed a systematic review of the literature describing the incidence and management of SSIs after inguinal hernia repair in LMHDICs. We conducted qualitative and quantitative analyses of manuscripts describing patients undergoing hernia repair to establish a baseline SSI rate for this procedure in these settings.Three hundred twenty-three abstracts were identified after applying search criteria, and 31 were suitable for the quantitative analysis. The overall pooled SSI rate was 4.1 infections/100 open hernia repairs (95% confidence interval [CI] 3.0-5.3 infections/100 open repairs), which is consistent with infection rates from high-human development index countries. A separate subgroup analysis of laparoscopic hernia repairs found a weighted pooled SSI rate of 0.4 infections/100 laparoscopic repairs (95% CI 0-2.4 infections/100 laparoscopic repairs).As surgical access continues to expand in LMHDIC settings, it is imperative to monitor surgical outcomes and ensure that care is provided safely. Establishing a baseline SSI rate for inguinal hernia repairs offers a useful benchmark for future studies and surgical programs in these countries.
View details for DOI 10.1089/sur.2017.154
View details for PubMedID 29048997
- Axillary reverse mapping with indocyanine green or isosulfan blue demonstrate similar crossover rates to radiotracer identified sentinel nodes Journal of Surgical Oncology 2017
Surgical Site Infections after Appendectomy Performed in Low and Middle Human Development-Index Countries: A Systematic Review.
Acute appendicitis is a common surgical emergency worldwide. Early intervention is associated with better outcomes. In low and middle Human Development-Index Countries (LMHDICs), late presentation and poor access to healthcare facilities can contribute to greater illness severity and higher complication rates, such as post-operative surgical site infections (SSIs). The current rate of SSIs post-appendectomy in low- and middle-index settings has yet to be described.We performed a systemic review of the literature describing the incidence and management of SSIs after appendectomy in LMHDICs. We conducted qualitative and quantitative analysis of the data in manuscripts describing patients undergoing appendectomy to establish a baseline SSI rate for this procedure in these settings.Four hundred twenty-three abstracts were initially identified. Of these, 35 studies met the criteria for qualitative and quantitative analysis. The overall weighted, pooled SSI rated were 17.9 infections/100 open appendectomies (95% confidence interval [CI] 10.4-25.3 infections/100 open appendectomies) and 8.8 infections/100 laparoscopic appendectomies (95% CI 4.5-13.2 infections/100 laparoscopic appendectomies). The SSI rates were higher in complicated appendicitis and when pre-operative antibiotic use was not specified.Observed SSI rates after appendectomy in LMHDICs are dramatically higher than rates in high Human Development-Index Countries. This is particularly true in cases of open appendectomy, which remains the most common surgical approach in LMHDICs. These findings highlight the need for SSI prevention in LMHDICs, including prompt access to medical and surgical care, routine pre-operative antibiotic use, and implementation of bundled care packages and checklists.
View details for DOI 10.1089/sur.2017.188
View details for PubMedID 29058569
- Regression of experimental NIS-expressing breast cancer brain metastases in response to radioiodide/gemcitabine dual therapy ONCOTARGET 2016; 7 (34): 54811-54824
Palliative Surgery for Advanced Cancer: Identifying Evidence-Based Criteria for Patient Selection: Case Report and Review of Literature
JOURNAL OF PALLIATIVE MEDICINE
2016; 19 (1): 22-29
Criteria for selecting patients with advanced cancer for palliative surgery (PS) remains poorly defined. Decision making for PS requires realistic treatment goals with well-defined criteria. Here we discuss a 71-year-old Jehovah's Witness with advanced stage renal cell carcinoma (RCC) who presented with profound anemia due to intractable bleeding from gastric metastasis. After repeated attempts with endoscopic and angiographic management, she underwent surgical palliation. Through this case, we developed 10-item evidence-based criteria for selecting patients for PS.The study objective was to provide a review of pertinent literature for PS and identify evidence-based criteria for patient selection. These criteria were relevant for selecting this patient with metastatic RCC and may prove beneficial for selecting advanced cancer patients for PS.A MEDLINE search revealed 175 publications relevant to PS. Among these, 17 articles defining patient selection criteria (PSC) were reviewed. A frequency-based analysis of each criterion was performed. Another search returned 30 cases of RCC gastric metastases from 25 published reports. Outcome analysis was determined by the Kaplan-Meier actuarial method.Ten criteria were identified: symptom control, prognosis, preoperative performance status, quality of life (QoL), tumor burden amenable to palliation, procedure-related morbidity and mortality, feasibility of nonsurgical therapies, anticipated hospitalization, requirement for additional palliation, and cost. This patient met all inclusion criteria and underwent a successful gastrectomy. Median survival for patients with RCC gastric metastasis was 20 months.This report illustrates an example of implementation of evidence-based criteria for selecting advanced cancer patients for PS. Validation of these criteria is warranted.
View details for DOI 10.1089/jpm.2015.0146
View details for Web of Science ID 000367057700007
View details for PubMedID 26565437
Pancreatic mucinous cystic neoplasm in a transgender patient
WORLD JOURNAL OF SURGICAL ONCOLOGY
Cystic pancreatic lesions are increasingly more frequent detected clinical entities. Mucinous cystic neoplasm (MCN) is a hormone-related pancreatic tumor (HRTP) with a strong predominance in young and middle-aged females.Here, we present the case of a 31-year-old surgically transgendered female-to-male patient with a history of alcoholic pancreatitis, on chronic testosterone therapy. He was found to have a pancreatic MCN and underwent distal pancreatectomy and splenectomy.To our knowledge, this is the first reported case of a transgender patient with a history of hormone replacement therapy (HRT) and pancreatic MCN. We consider possible mechanisms for the pathogenesis to explain this patient's neoplasm.
View details for DOI 10.1186/s12957-015-0620-8
View details for Web of Science ID 000357085900001
View details for PubMedID 26104783
View details for PubMedCentralID PMC4486435
Richter-type Spigelian hernia: A case report and review of the literature.
International journal of surgery case reports
2015; 6C: 160-162
Abdominal wall hernias through the arcuate line termed Spigelian hernias are uncommon. These hernias presenting as a Richter-type, with strangulation of part of the circumference of the bowel wall is very rare.We report a 27-year-old male patient who presented with a Richter-type Spigelian hernia.A MEDLINE literature search of this rare entity yielded six publications presenting Richter-type Spigelian hernias. All of these articles and accompanying references were thoroughly reviewed. There was no gender or anatomical side predominance among the patients. All except our patient presented here were elderly. Pain was the most common symptom and was present in all patients. All patients underwent surgical repair and none reported recurrence of their hernia afterwards.Richter-type Spigelian hernia is rare and has been reported infrequently in the existing literature. Clinical diagnosis is challenging and CT scan is the diagnostic study of choice. Surgical repair is the definitive treatment and involves primary or mesh repair of the defect as appropriate. Necrotic bowel should be resected and we recommend biologic mesh repair in these cases if the defect is large.
View details for DOI 10.1016/j.ijscr.2014.10.088
View details for PubMedID 25544481
View details for PubMedCentralID PMC4334998
Evaluation of three rapid diagnostic tests for the detection of human infections with Plasmodium knowlesi
Plasmodium knowlesi, a malaria parasite of Southeast Asian macaques, infects humans and can cause fatal malaria. It is difficult to diagnose by microscopy because of morphological similarity to Plasmodium malariae. Nested PCR assay is the most accurate method to distinguish P. knowlesi from other Plasmodium species but is not cost effective in resource-poor settings. Rapid diagnostic tests (RDTs) are recommended for settings where malaria is prevalent. In this study, the effectiveness of three RDTs in detecting P. knowlesi from fresh and frozen patient blood samples was evaluated.Forty malaria patients (28 P. knowlesi, ten P. vivax and two P. falciparum) diagnosed by microscopy were recruited in Sarawak, Malaysian Borneo during a 16-month period. Patient blood samples were used to determine parasitaemia by microscopy, confirm the Plasmodium species present by PCR and evaluate three RDTs: OptiMAL-IT, BinaxNOW® Malaria and Paramax-3. The RDTs were also evaluated using frozen blood samples from 41 knowlesi malaria patients.OptiMAL-IT was the most sensitive RDT, with a sensitivity of 71% (20/28; 95% CI = 54-88%) for fresh and 73% (30/41; 95% CI = 59-87%) for frozen knowlesi samples. However, it yielded predominantly falciparum-positive results due to cross-reactivity of the P. falciparum test reagent with P. knowlesi. BinaxNOW® Malaria correctly detected non-P. falciparum malaria in P. knowlesi samples but was the least sensitive, detecting only 29% (8/28; 95% CI = 12-46%) of fresh and 24% (10/41; 95% CI = 11-37%) of frozen samples. The Paramax-3 RDT tested positive for P. vivax with PCR-confirmed P. knowlesi samples with sensitivities of 40% (10/25; 95% CI = 21-59%) with fresh and 32% (13/41; 95% CI = 17-46%) with frozen samples. All RDTs correctly identified P. falciparum- and P. vivax-positive controls with parasitaemias above 2,000 parasites/μl blood.The RDTs detected Plasmodium in P. knowlesi-infected blood samples with poor sensitivity and specificity. Patients with P. knowlesi could be misdiagnosed as P. falciparum with OptiMAL-IT, P. vivax with Paramax-3 and more correctly as non-P. vivax/non-P. falciparum with BinaxNOW® Malaria. There is a need for a sensitive and specific RDT for malaria diagnosis in settings where P. knowlesi infections predominate.
View details for DOI 10.1186/1475-2875-13-60
View details for Web of Science ID 000332774300003
View details for PubMedID 24548805
View details for PubMedCentralID PMC3931291
Ex vivo Evans blue assessment of the blood brain barrier in three breast cancer brain metastasis models.
Breast cancer research and treatment
2014; 144 (1): 93-101
The limited entry of anticancer drugs into the central nervous system represents a special therapeutic challenge for patients with brain metastases and is primarily due to the blood brain barrier (BBB). Albumin-bound Evans blue (EB) dye is too large to cross the BBB but can grossly stain tissue blue when the BBB is disrupted. The course of tumor development and the integrity of the BBB were studied in three preclinical breast cancer brain metastasis (BCBM) models. A luciferase-transduced braintropic clone of MDA-231 cell line was used. Nude mice were subjected to stereotactic intracerebral inoculation, mammary fat pad-derived tumor fragment implantation, or carotid artery injections. EB was injected 30 min prior to euthanasia at various timepoints for each of the BCBM model animals. Serial bioluminescent imaging demonstrated exponential tumor growth in all models. Carotid BCBM appeared as diffuse multifocal cell clusters. EB aided the localization of metastases ex vivo. Tumor implants stained blue at 7 days whereas gross staining was not evident until day 14 in the stereotactic model and day 28 for the carotid model. EB assessment of the integrity of the BBB provides useful information relevant to drug testing in preclinical BCBM models.
View details for DOI 10.1007/s10549-014-2854-5
View details for PubMedID 24510011
View details for PubMedCentralID PMC4363122
Two treatments, one disease: childhood malaria management in Tanga, Tanzania
In the Tanga District of coastal Tanzania, malaria is one of the primary causes of mortality for children under the age of five. While some children are treated with malaria medications in biomedical facilities, as the World Health Organization recommends, others receive home-care or treatment from traditional healers. Recognition of malaria is difficult because symptoms can range from fever with uncomplicated malaria to convulsions with severe malaria. This study explores why caregivers in the Tanga District of Tanzania pursue particular courses of action to deal with malaria in their children.Qualitative data were collected through interviews with three samples: female caregivers of children under five (N = 61), medical practitioners (N = 28), and traditional healers (N = 18) in urban, peri-urban, and rural areas. The female caregiver sample is intentionally stratified to reflect the greater population of the Tanga District in level of education, marital status, gender of household head, religion, and tribal group affiliation. Qualitative data were counted, coded and analysed using NVivo7 software.Results indicate that a variety of factors influence treatment choice, including socio-cultural beliefs about malaria symptoms, associations with spiritual affliction requiring traditional healing, knowledge of malaria, and fear of certain anti-malaria treatment procedures. Most notably, some caregivers identified convulsions as a spiritual condition, unrelated to malaria. While nearly all caregivers reported attending biomedical facilities to treat children with fever (N = 60/61), many caregivers stated that convulsions are best treated by traditional healers (N = 26/61). Qualitative interviews with medical practitioners and traditional healers confirmed this belief.Results offer insight into current trends in malaria management and have implications in healthcare policy, educational campaigns, and the importance of integrating traditional and biomedical approaches.
View details for DOI 10.1186/1475-2875-8-240
View details for Web of Science ID 000272254600001
View details for PubMedID 19860900
View details for PubMedCentralID PMC2779815