| Geographic distribution and spatial analysis of Leishmania infantum infection in domestic and wild animal reservoir hosts of zoonotic visceral leishmaniasis in Iran: A systematic review M Mohebali, E Moradi-Asl, Y Rassi Journal of Vector Borne Diseases 2018 55(3):173-183 Visceral leishmaniasis (VL) is an important parasitic disease which is endemic in different parts of Iran; and domestic and wild canines are principal reservoir hosts of the disease. The objective of this study was to review the spatial distribution of canine VL (CVL) caused by Leishmania infantum in domestic and wild canines in different geographical areas of Iran. An extensive literature search was conducted in different international and national databases, including Cochrane, MEDLINE/PubMed, Scopus, Web of Science and Iran Medex to find articles with the words “visceral leishmaniasis in Iran” in their titles and “canine visceral leishmaniasis in Iran” or “feline visceral leishmaniasis in Iran” or “accidental reservoir hosts of visceral leishmaniasis in Iran” in their subtitles, irrespective of the type and duration of study. Screening of the irrelevant articles from total 36,342, yielded 61 eligible articles. More than 93% of the studies were carried out on domestic dogs (Canis familiaris, n = 57) and the remaining were on other carnivores such as wild canines including foxes (Vulpes vulpes, n = 4), jackals (C. aureus, n = 6) and wolves (C. lupus, n = 6); while studies on domestic cats (Felis catus, n = 3) as well as desert rodents (n = 2) were rare. The average rate of L. infantum infections reported among domestic dogs using direct agglutination test (DAT) in Iran was 12.5%. The highest prevalence rate (14%) was reported from the northwest regions of the country where VL is endemic. The review indicates that CVL is endemic in various parts of Iran and domestic dogs are the main and potential reservoir hosts of the disease. Other carnivores, such as domestic cats and some species of desert rodents (Cricetulus migratorius, Mesocricetus auratus and Meriones persicus) seem to be playing a role in the maintenance of transmission cycle of L. infantum in the endemic areas of the disease. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| A laboratory simulation study on suppression of resistance genes by differential exposures to an insecticide in Anopheles stephensi Liston population Vaishali Verma, OP Agrawal, Poonam Sharma Velamuri, Kamaraju Raghavendra Journal of Vector Borne Diseases 2018 55(3):184-188 Background & objectives: Insecticide applied at optimum dosage and coverage delays the development of resistance in disease vectors. The study was aimed to test the hypothesis whether decrease in exposure to insecticide leads to decrease in selection of insecticide resistance in mosquitoes. The mosquitoes were variably exposed to insecticide in the laboratory by simulating the variations in insecticide sprays applied in the field. Methods: The study was carried out on DDT resistant adults of Anopheles stephensi. Mosquitoes were differentially exposed to impregnated papers of DDT (4%), that were differentially masked to 25, 50, and 75% area with an unimpregnated Whatman No.1 filter paper, and to a positive control without any masking, i.e. 100% exposure area. The study was conducted for five generations and at each generation mosquitoes were exposed to differentially masked impregnated papers, and percent mortality was calculated. Results: The observed survival rate in differential exposures was more with the increase in heterozygous genotype resistance-susuceptible (RS) frequency. Resistant gene frequency with differential exposures (25 to 75%) was in the range of 0.38–0.54 for the F0 generation, which increased to 0.84–0.93 for the F4 generation. In 100% exposure it was 0.18 in F0 generation, which increased to 0.58 in the F4 generation. The resistant gene frequencies in the population showed increasing trend with decrease in exposure in contrast to complete exposure. Interpretation & conclusion: Variable simulated exposures resulted in precipitation of increased resistance while complete exposure resulted in lower levels of resistance, signifying the importance of optimum dosage and coverage in the indoor residual spray in delaying/avoiding the development of insecticide resistance in the disease vectors. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Prevalence of disease vectors in Lakshadweep Islands during post-monsoon season Jayalakshmi Krishnan, L Mathiarasan Journal of Vector Borne Diseases 2018 55(3):189-196 Background & objectives: Increase of vector-borne diseases (VBDs) in India has posed a question on the situation in Lakshadweep Islands, where VBDs are reported from time-to-time. The present investigation was aimed to assess the faunastic situation of the prevailing vectors along with their breeding sites in different islands of the Lakshadweep. Methods: Extensive surveys were carried out from November 2017 to January 2018 (post-monsoon season) randomly in the nine inhabited islands of Lakshadweep for conducting faunastic studies on mosquitoes and to know the basic binomics like breeding and resting preference of mosquitoes. The study islands included, Kavaratti, Agatti, Chetlat, Bitra, Amini, Kadmath, Andrott, Kalpeni and Kiltan. Both immature and adult collections were carried out by standard/appropriate sampling techniques. The obtained data were calculated and analysed in terms of different entomological indices Results: A total of 3356 mosquitoes were collected during the study period which comprised of 16 species from nine genera. Out of the 16 species, six belonged to mosquito vectors. The collection included malaria vector, Anopheles stephensi; Japanese encephalitis vector, Culex tritaeniorhynchus; Bancroftian filariasis vector, Cx. quinquefasciatus; Brugian filariasis vector, Mansonia uniformis; and dengue and chikungunya vectors, Stegomya albopicta and St. aegypti. Stegomya albopicta was the most predominant species observed constituting 54% of the catch, followed by Cx. quinquefasciatus, An. stephensi, Cx. tritaeniorhynchus, and St. aegypti constituting 10.5, 6, 3 and 1.2%, respectively. Apart from vector species many non-vectors such as Heizmannia chandi, An. subpictus, An. varuna, Cx. sitiens, Cx. minutissimus, Cx. rubithoracis, Fredwardsius vittatus, Lutzia fuscana, Malaya genurostris and Armigeres subalbatus were also present in the study area. In Kavaratti Island, the capital of Lakshadweep, a non-vector species of sandfly, Sergentomyia (Parrotomyia) babu was observed during the indoor resting collection. The major breeding sites which supported various mosquito species included, discarded plastic containers, tree holes, open sintex tanks (water storage tanks), unused wells, discarded tyres, discarded iron pots, unused and damaged boats, cement tanks, pleated plastic sheets, coral holes, pits and irrigation canals, discarded washing machines, and Colocasia plant leaf axils. Breteau index ranged between 65.3 and 110, CI ranged between 63.64 and 72.41; and HI ranged between 38.46 and 70 among the various islands. Interpretation & conclusion: Entomological indices such as house index (HI), breteau index (BI) and pupal index (PI) were high in all the nine islands and exceeded the threshold levels specified by WHO, indicating high risk for dengue virus transmission in case of outbreaks. Occurrence of vector as well as non-vector species indicates that the global change in climate is causing notable changes in terms of breeding of vector and non-vector species in the islands. With the reported cases of VBDs and the presence of vectors species in Lakshadweep Islands, a stringent control measure needs to be implemented at the Lakshadweep Islands. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Comparison of the effectiveness of two-dose versus three-dose sulphadoxine-pyrimethamine in preventing adverse pregnancy outcomes in Nigeria Nneka U Igboeli, Maxwell O Adibe, Chinwe V Ukwe, Cletus N Aguwa Journal of Vector Borne Diseases 2018 55(3):197-202 Background & objectives: Three doses of intermittent preventive treatment with sulphadoxine-pyrimethamine (IPTp-SP) has been adopted as the new recommendation for prevention of malaria in pregnancy. This study evaluated the effectiveness of two-dose versus three-dose of SP for IPTp-SP in the prevention of low birth weight (LBW) and malaria parasitaemia. Methods: An open, randomized, controlled, longitudinal trial was conducted in a secondary level hospital in Nsukka region of Enugu State, Nigeria. A sample of 210 pregnant women within gestational ages of 16–24 wk were recruited at antenatal clinics and equally randomized to either a two-dose SP or three-dose SP group. The primary endpoints were LBWs, peripheral, and placental parasitaemia, while the secondary endpoints were maternal anaemia, pre-term birth, clinical malaria and adverse effects of SP. Results: Among 207 cases followed till delivery, the prevalence of parasitaemia was lower in three-dose group than in two-dose group for both peripheral (9.3% versus 27.8%) and placental (10.6% versus 25.6%) parasitaemia. The adjusted odds ratios (aOR) were 0.15 [95% confidence interval (CI), 0.05 – 0.45] and 0.17 (95% CI, 0.06–0.51), respectively. The prevalence of LBW was also lower in three-dose (3.5%) than in two-dose (12.2%) group (aOR, 0.15; 95% CI, 0.04–0.63); however, the prevalence of maternal anaemia, pre-term births, clinical malaria and SP adverse effects were similar between the two arms of treatment. Interpretation & conclusion: Addition of a third SP dose to the standard two-dose SP for IPTp led to improved reductions in the risk of some adverse pregnancy outcomes. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Changing paradigm in the epidemiology of Japanese encephalitis in a non-endemic region P Philip Samuel, V Thenmozhi, M Muniaraj, D Ramesh, S Victor Jerald Leo, T Balaji, K Venkatasubramani, J Nagaraj, R Paramasivan Journal of Vector Borne Diseases 2018 55(3):203-207 Background & objectives: Japanese encephalitis (JE) is a mosquito-borne zoonotic disease. The JE virus (JEV) does not cause any disease among its natural hosts and transmission continues through mosquitoes belonging to Culex vishnui subgroup. This study was aimed to investigate the prevalence of JEV in mosquitoes and humans in the Thanjavur district, a non-endemic region for JE, in Tamil Nadu, by using standard available assays. Methods : A sero-surveillance study was conducted in Thanjavur district among the normal rural school children in the 5–12 yr age group, during the JE season (October) and post-JE season (February) from 2011 to 2013 for the detection of JEV infection. Vector abundance studies were carried out from 2011 to 2014. JE seropositivity and its association between the seasons were analysed statistically. Results : The occurrence of JE infection among children aged 5–12 yr was very high in the study area. The infection rates for JE in two consecutive seasons for 2011–12 and 2012–13 were 32.2 and 65.2%, respectively. The Cx. tritaeniorhynchus sp. dominated the catch, and was majorly responsible for the transmission. There was a significant difference in the human infection rate compared to the years 1991–92 and 1992–93; and a marked decrease in the cattle to pigs ratio (123 : 1) compared to the studies in 1991–93. Interpretation & conclusion : The study unearthed the prevailing situation of JE among children, who are at higher risk of developing the disease during the transmission season. The decrease in the cattle to pigs ratio might be the one of the reasons for increase in the JEV infection among the children population compared to 20 years before. This trend requires urgent attention as it could be prevented with effective surveillance systems and vaccines. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Spatial risk analysis on occurrences and dispersal of Biomphalaria straminea in and endemic area for schistosomiasis Elainne Christine de Souza Gomes, Millena Carla da Silva Mesquitta, Leandro Batista Wanderley, Fábio Lopes de Melo, Ricardo José de Paula Souza e Guimarães, Constança Simões Barbosa Journal of Vector Borne Diseases 2018 55(3):208-214 Background & objectives : Schistosomiasis is a rural endemic disease that has been expanding to urban and coastal areas in the state of Pernambuco, Brazil. The aim of this study was to characterize the distribution of breeding sites of the causative vector, Biomphalaria straminea in an endemic municipality for schistosomiasis and to present the predictive models for occurrences and dispersal of this vector snail to new areas. Methods : A malacological survey was conducted during January to December 2015 in the municipality of São Lourenço da Mata, Pernambuco, Brazil to identify the breeding sites of Biomphalaria. Faecal contamination was determined by means of the Colitag™ diagnostic kit. Rainfall data were collected, and correlated with snail distribution data. Kernel density estimation, kriging and maximum entropy (MaxEnt) modeling were used for spatial data analysis, by means of the spatial analysis software packages. Results : Out of the 130 demarcated collection points, 64 were classified as breeding sites for B. straminea. A total of 5,250 snails were collected from these sites. Among these 64 sites, four were considered as foci of schistosomiasis transmission and 54 as potential transmission foci. An inverse relationship between rainfall and snail density was observed. Kernel spatial analysis identified three areas at higher risk of snail occurrence, which were also the areas of highest faecal contamination and included two transmission foci. Kriging and MaxEnt modeling simulated the scenarios obtained through the kernel analyses. Interpretation & conclusion : Use of geostatistical tools (Kriging and MaxEnt) is efficient for identifying areas at risk and for estimating the dispersal of Biomphalaria species across the study area. Occurrence of B. straminea in the study area is influenced by the rainy season, as it becomes more abundant during the period immediately after the rainy season, increasing the risk of dispersal and the appearance of new transmission foci. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Evaluation of epidemiological, clinical, and laboratory characteristics and mortality rate of patients with Crimean-Congo hemorrhagic fever in the northeast region of Turkey Faruk Karakecili, Aytekin Cikman, Merve Aydin, Umut Devrim Binay, Ozan Arif Kesik, Fatih Ozcicek Journal of Vector Borne Diseases 2018 55(3):215-221 Background & objectives : Crimean-Congo hemorrhagic fever (CCHF), an illness characterized by fever and hemorrhage, is caused by a CCHF virus (CCHFV). It is an important public health problem in Turkey. The objective of this study was to evaluate the demographic, clinical, and laboratory characteristics and mortality rates of CCHF patients in the northeast region of Turkey. Methods : A total of 206 patients, diagnosed with CCHF, from northeast region of Turkey were included and evaluated between 2011 and 2017. Real-time reverse transcriptase polymerase chain reaction (RT-PCR) and immunofluorescence (IFA) methods were used for the diagnoses. Results : Of the patients included in the study, 77.2% were farmers/livestockers, while 22.8% had other occupations. The incidence of tick bite or tick contact with bare hands was 52.9%. About 94.2% of the patients were living in rural areas and 5.8% in city centers. However, all the patients living in city centers had a history of visit to rural areas. The disease was more common in May, June, and July months. The most common symptoms at the time of admission included fatigue, fever, and widespread body pain, while laboratory findings were thrombocytopenia, leukopenia, and anemia. Bleeding, tachycardia, and rash were the most common findings on physical examination. Of all the patients, 95.6% were identified by RT-PCR and 4.4% by IFA methods. Severe cases constituted 22.3% (46) of the included patients. Throughout the course of this study, 7 (3.4%) patients died, and the remaining 96.6% (199) patients were discharged with a full recovery. Disease severity was significantly correlated with mortality rate and duration of hospitalization (p <0.001 and p = 0.013). Interpretation & conclusion : In this study, the mortality rate observed was lower than that reported in the literature because of accessibility of early supportive therapy. It would be beneficial in CCHF treatment to recognize the disease at an early stage, begin supportive treatment quickly, and educate the people living in high-risk areas as well as health care personnel working in these areas. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Babesiosis prevalence in malaria-endemic regions of Colombia Juliana Gonzalez, Ignacio Echaide, Adriana Pabón, J Juan Gabriel Piñeros, Silvia Blair, Alberto Tobón-Castaño Journal of Vector Borne Diseases 2018 55(3):222-229 Background & objectives : The presence of Babesia spp in humans, bovine cattle and ticks (the transmitting vector) has not been well characterized in Colombia. Babesia infection in humans can be overlooked due to similarity of the disease symptoms with malaria specially in the regions where malaria is endemic. The aim of the present work was to study the frequency of Babesia infection in humans, bovines and ticks in a malaria endemic region of Colombia, and explore the possible relationship of infection with host and the environmental factors. Methods : A cross-sectional study was carried out between August 2014 and March 2015 to determine the frequency of B. bovis and B. bigemina infection in a sample of 300 humans involved in cattle raising, in 202 bovines; and in 515 ticks obtained from these subjects, using molecular (PCR), microscopic and serological methods. In addition, the demographic, ecological and zootechnical factors associated with the presence of Babesia, were explored. Results : In the bovine population, the prevalence of infection was 14.4% (29/202); the highest risk of infection was found in cattle under nine months of age (OR = 23.9, CI 8.10–94.30, p = 0.0). In humans, a prevalence of 2% (6/300) was found; four of these six cases were positive for B. bovis. Self-report of fever in the last seven days in the positive cases was found to be associated with Babesia infection (Incidence rate ratio = 9.08; CI 1.34–61.10, p = 0.02). The frequency of B. bigemina infection in the collected ticks was 18.5% (30/162). Interpretation & conclusion : The study established the presence of Babesia spp in humans, bovines and ticks. The most prevalent species responsible for babesiosis in humans and bovines was B. bovis, while B. bigemina was the species most frequently found in the tick population. The results contribute to the knowledge of the epidemiology of babesiosis in the country and can provide guidelines for the epidemiological surveillance of this non-malarial febrile illness in humans as well as cattle. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Low susceptibility of domestic cats to experimental Leishmania infantum infection Baharak Akhtardanesh, Reza Kheirandish, Iraj Sharifi, Ali Mohammadi, Ali Mostafavi, Tohid Mahmoodi, Mohadesse Ebrahimi Journal of Vector Borne Diseases 2018 55(3):230-234 Background and objectives : The dogs are considered the main reservoir of visceral leishmaniasis (VL), but lately the disease incidence has been reported in cats also. In this study, the susceptibility of domestic cats to experimental Leishmania infantum infection was assessed by different diagnostic methods. Methods : A total of 12 healthy adult male cats were captured by double door live trap cages containing baits. Of them eight cats were intraperitoneally inoculated with 107 L. infantum promastigotes (stationary phase), and four cats were used as controls. Whole blood and serum samples were collected at weekly intervals for 16 wk after inoculation for testing by polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) methods. Aspirates of prescapular lymph nodes and bone marrow were obtained at monthly intervals. Clinical examination was performed twice weekly and histopathological evaluation was done on necropsy samples at the termination of the study. Results: One week after inoculation, blood nested PCR was able to detect the L. infantum infection and it remained positive until 16 wk. ELISA test remained negative during the study. Amastigote phase of parasite was not observed in bone marrow aspiration and necropsy samples. Interpretation and conclusion : The feline model described in this work would be useful in further understanding of L. infantum immunopathogenensis in cats. The results of this preliminary study suggest that cats might be resistant to VL as the inoculation dose which induces pathognomonic clinical features in dogs, just creates asymptomatic parasitaemia in cats. Though, due to long-lasting parasitaemia, cats may act as appropriate reservoir for transmission of VL to human population. Further studies are needed to describe the possible role of cats in the epidemiology of VL in endemic areas. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Adaptation of Aedes aegypti to salinity: Characterized by larger anal papillae in larvae SN Surendran, K Sivabalakrishnan, T.T.P. Jayadas, S Santhirasegaram, A Laheetharan, M Senthilnanthanan, R Ramasamy Journal of Vector Borne Diseases 2018 55(3):235-238
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Friday, January 4, 2019
Vector Borne Diseases
Management of Carotid Artery Injury in Endonasal Surgery
PMCID: PMC4399584
PMID: 25992141
Management of Carotid Artery Injury in Endonasal Surgery
This article has been cited by other articles in PMC.
Introduction
Across the world, the transnasal endoscopic approach is fast becoming the method of choice for managing pathology of the ventral skull base including the clivus and craniocervical junction.1 Endoscopic techniques employed for the surgical management of inflammatory and neoplastic diseases in the paranasal sinuses have been expanded and combined with a better understanding of endonasal skull base anatomy to facilitate surgery in this region.2 Otolaryngologists and neurosurgeons appreciate the advantages of this method including the avoidance of skin incisions, minimal sacrifice of intervening structures, improved visualization, reduced postoperative pain, and shorter hospital admissions.3
Despite these significant advantages, the limitations of this approach must also be appreciated. These include longer operating times and a reported higher postoperative cerebrospinal fluid leak rate.4 5 The most feared and disastrous complication, however, is that of carotid artery injury. In the immediate operative setting, this can result in overwhelming blood loss and place the patient's life at imminent risk.6These patients may also be susceptible to pseudoaneurysm formation, vessel spasm, thrombosis, embolism with consequent cerebral insult, and even the formation of a caroticocavernous fistula.7
The incidence of carotid artery injury in endoscopic sinus surgery is rare, with only 29 case reports described in the literature.2 The incidence is higher in transsphenoidal pituitary surgery at 1.1% and higher still in extended endonasal approaches, such as for craniopharyngiomas, clival chordomas, and chondrosarcomas, at 5 to 9%.8
Currently, there is no standard protocol for the management of carotid artery injury. Literature in this area is largely limited to case reports and anecdotal evidence. With the increasing frequency of endonasal procedures performed and the willingness to tackle more complex pathologies, the appropriate management of this catastrophic complication has become increasingly important. As such, attention has been turned toward prospective research, which has been aided by the development of a sheep model of carotid bleeding.9 This, in combination with the emergence of vascular training workshops, has allowed surgeons to gain the expertise necessary to manage this scenario safely.10 11 12
This article aims to review the preoperative, operative, and postoperative evidence-based management of carotid artery injury.
Review of the Literature
Preoperative Considerations
The successful evolution of endoscopic skull base surgery from paranasal sinus surgery has relied on the surgeon's thorough understanding of anatomy. This anatomical knowledge can be an integral part of the prevention of carotid artery injury. Adoption of a classification system based on different endoscopic approaches, such as the one described by Kassam et al, can help minimize neurovascular complications by augmenting the surgeon's anatomical knowledge.13 14 15
Identifying at-risk patients, however, is the mainstay of carotid artery injury prevention. A recent review article by Valentine and Wormald identified anatomical, tumor, and patient factors that may contribute to carotid artery injury.8
Anatomical Factors
Appreciation of the relationship between the internal carotid artery (ICA) and the sphenoid sinus is paramount. The bony wall overlying the ICA is less than 0.5 mm thick and is not sufficient to protect the artery.16 Also, in up to 22% of cases the lateral sphenoid wall may in fact be dehiscent with only dura and sphenoid sinus mucosa overlying the ICA.16 17 An ICA that approaches the midline may also predispose to injury. It has been found that in 71% of cases the artery may be up to 4 mm from the midline, with some authors also describing the distance between both ICAs within the sphenoid to be as close as 4 mm.18 19 In the majority of patients, the bony sphenoid septum or sphenoid septation inserts onto the ICA canal wall, and surgery on this septation may place the artery at risk.20
Potential cavernous ICA anomalies also need to be taken into account. Cavernous ICA aneurysm makes up ∼12% of all intracranial aneurysms, with some authors showing an association with pituitary adenomas. Of concern are several reports of unrecognized preoperative cavernous ICA aneurysms, which have resulted in ICA rupture.8
Tumor Factors
Tumors closely adherent to the ICA require careful attention. Vessel encasement by the tumor not only predisposes to injury but may also be associated with vasospasm, which can result in altered mental status and/or hemiparesis.21 Vasospasm can occur as a result of tumor dissection away from the ICA or due to displacement of the ICA within the cavernous sinus during attempted hemostasis.22 The authors advocate whenever possible to use blunt instruments, such as suction Freer dissectors and pituitary ring curettes, when working in close proximity to the artery. If bone is required to be removed, then a grasping and twisting motion should be avoided. Performing bony osteotomies before removal can help prevent inadvertent laceration. In addition, diamond burrs should be utilized in preference to cutting burrs.
Taking into account both anatomical and tumor factors requires imaging to be a mandatory part of the preoperative process. High-definition, thin-sliced computed tomography (CT) scans can be useful to thoroughly visualize the bony anatomy of the sella region and delineate vessel anatomy and its relationship to the sphenoid sinus. Magnetic resonance imaging (MRI) scans can demonstrate preoperative ICA aneurysms, with follow-up magnetic resonance angiogram (MRA) useful to confirm such suspicions.2 8Intraoperative CT can provide up-to-date information for image guidance and can detect vascular complications.2 In addition, neurophysiologic monitoring of cortical and brainstem function during surgery can be helpful in the event of major bleeding to assess cerebral blood flow.2
Patient Factors
A careful patient history is integral to the preoperative workup. Several authors have described the association between cavernous ICA injuries and patients who have had previous radiotherapy, revision surgery, and/or bromocriptine therapy. Also, acromegalic patients tend to have more tortuous and ectatic carotid arteries, often with tumor in contact or surrounding the carotid.6 8 22 23
Intraoperative Management
A major vascular injury such as a carotid artery injury represents one of the most challenging scenarios for a surgeon. The high-pressure, high-flow environment can prove difficult for even the most experienced surgeon to gain visualization and control. Before attempting hemostasis, it is important for the surgical team to appropriately control the surgical field to prevent a panicked and disordered approach, to promote safe maneuvers, and to ensure controlled management.
Controlling the Surgical Field
The literature relating to the endoscopic control of major vascular injury is limited. Through the development of an animal model of the endoscopic, endonasal vascular injury,9 Valentine and Wormald were able to reproduce the high-pressure, high-volume field encountered during carotid artery injury and as such described key steps in its control.10
Key points include10:
- Two surgeons are engaged, allowing one surgeon to control the bloodstream, directing it away from the endoscope, while the other obtains visualization to attempt hemostasis (Fig. 1).
Controlling the surgical field: suction device directs blood flow away from endoscope to allow attempt at hemostasis with Wormald vascular clamp (Medtronic, Jacksonville, Florida, United States).
- Two large-bore (10F) suction devices and, if available, a lens cleaning system for the endoscope should be used.
- The second surgeon uses suction downside the nose with predominant bleeding to direct flow away from the other side.
- The primary surgeon places the endoscope down the contralateral side, using the posterior septal edge as a shield from the blood flow.
- The primary surgeon clears blood ahead of the endoscope using the second suction device. A pedicled septal flap should also be cleared and pushed into the nasopharynx.
- The second surgeon is then free to "hover" the suction device directly over the site of injury to help gain visualization for the primary surgeon.
Hemostasis
A variety of methods to gain control of a vascular catastrophe have been reported. Emergency surgical ligation in the neck has been a traditional approach; however, this can result in stroke or death and will be ineffective in the patient with good collateral flow. Ligation will also terminate access for any potential endovascular procedure.6 24 25 Nasal packing is currently therefore the mainstay of management.8 25 26
A number of adjunct maneuvers and procedures have been described to aid in hemostasis and pack placement. Head elevation and controlled hypotension are not necessary given the significant hypotensive effect of the bleeding. If suction devices and hypotension cannot allow for adequate nasal packing, then ipsilateral common carotid artery compression can be performed.8 Weidenbecher et al advocated bilateral carotid artery compression in the neck, with concurrent surgical widening of the sphenoid sinus ostium, to facilitate nasal pack placement.17 It is also widely recommended that normotension be maintained through resuscitative measures to preserve adequate cerebral perfusion.8
Several packing agents have been described in the literature. These include Teflon (Medox Medical, Oakland, NJ) and methyl methacrylate patch, fibrin glue, Gelfoam (Pfizer, New York City, NY), oxidized cellulose packing thrombin-gelatin matrix, oxygel, and glue and muslin gauze.8 26 Valentine and Wormald's review article found that despite numerous options, gauze was most frequently used due to its availability and ease of use.8 Packing is not without its own complications, however. Raymond et al reported on 12 cases in which carotid artery injury was treated with nasal packing. Eight of these cases had ICA occlusion, and four had carotid stenosis secondary to the packing. It was concluded that overpacking contributed to patient morbidity and mortality.6 Skull base surgery requires wide exposure of the surgical field and exposure of many critical neurovascular structures. Overpacking is indeed an important consideration in preventing compression injury to these structures. Furthermore, compressive nasal packing is not considered an option if the dura is opened as blood is likely to track back into the subdural space.2As such, attention has therefore turned to alternate methods.
Muscle Patch
Considerable effort has been made in our department to add to the relative paucity of prospective research in the management of carotid artery injury. Valentine et al compared the hemostatic efficacy of various absorbable and biocompatible hemostats in an animal model of carotid bleeding. These included oxidized cellulose, thrombin-gelatin matrix, and a crushed muscle patch. The crushed muscle patch was the only method that succeeded in gaining hemostasis in all instances.11 Its effectiveness has been described in case reports in the past, with the use of quadriceps muscle as an effective permanent tamponade for ICA bleeding.17
Valentine's work was followed by Padhye et al's study in which the muscle patch was trialed not only on a linear injury type but also punch and stellate injuries. The muscle patch again achieved hemostasis in all cases. Long-term complications were also assessed, and although muscle patch use incurred low rates of destabilization and pseudoaneurysm in certain injury types, it was shown to maintain normal vessel characteristics and patency in all cases.12
In the clinical setting, muscle is harvested from the thigh (usually prepared for fascia lata graft in skull base cases) or sternocleidomastoid in the neck. A 2 × 1.5 × 1-cm graft is harvested then crushed between two metal kidney basins and, after gaining control of the surgical field, it is placed directly over the injury site with Blakesley forceps (Fig. 2).27 It should be placed with enough force to stay in contact with the vessel injury site but should not compress or occlude the vessel, and it may take up to 12 minutes to gain hemostasis.11 12 If the carotid is likely to be exposed to the nasal cavity, the muscle patch should be reinforced with an overlying septal flap. If the vessel is intracranial, the patch should be secured with oxidized cellulose and fibrin glue.
Muscle patch placed over carotid injury site with Blakesley forceps.
Direct Vessel Closure
In the situation where there is adequate exposure of the vasculature during surgery and the vessel injury site is not enclosed by bone or difficult to access, direct closure of the injury is possible.2 8 26
Laws and Solares et al have previously described the use of direct suture repair and a Sundt-type clip graft in cases of carotid artery injury; however, outcomes of these methods are not known.2 22 Valentine et al used of U-clip anastomotic device (Medtronic, Jacksonville, Florida, United States) to repair the injury site after clamping with a Wormald endoscopic vascular clamp (Medtronic) and found it to be very effective in gaining hemostasis in an animal model of carotid catastrophe.11 Long-term outcomes of this method are also unknown, and unfortunately Medtronic has ceased production of the U-clip.
Padhye et al studied different carotid injury types and their long-term complications and found that a T2 Aneurysm Clip (Mizuho, Tokyo, Japan) was able to gain hemostasis in all injury types as well as prevent pseudoaneurysm occurrence in an animal model of carotid bleeding (Fig. 3). Careful attention to placement was needed to avoid contributing to carotid stenosis.12
T2 aneurysm clip (Mizuho, Tokyo, Japan) placement on carotid injury site.
Bipolar electrocauterization has also been described2; however, long-term outcomes in a clinical setting are unknown. Padhye et al trialed bipolar electrocauterization on different injury types in an animal model of bleeding, and although effective at times in gaining hemostasis, there was an association with delayed secondary hemorrhage as well as total carotid occlusion. In addition, this technique can in certain cases worsen the injury, enlarging the defect. Therefore, this technique cannot be recommended.12
Endovascular Techniques
In some patients, hemostasis may not be achievable, and in these cases urgent transfer for endovascular intervention must be sought.25 28 29 These interventions are designed to either occlude the vessel or maintain vascular flow.8 In these cases, as much hemostasis as possible should be achieved endoscopically before transfer to the angiography suite.
Endovascular occlusion of the artery is generally performed using a balloon or coil and should be performed at the wall defect to prevent extravasation of blood from both anterograde and retrograde vessel filling.25 Deployment of an endovascular balloon or coil can be associated with distal migration due to the high-pressure, high-flow environment of the artery.30 This can place the ophthalmic artery at imminent risk due to its location distal to the cavernous ICA.6 If occlusive intervention is sought and time permits, prior assessment of collateral circulation should be undertaken and can be done in a variety of ways. In addition to angiography, balloon occlusion test (BOT) of the ICA in combination with electroencephalogram, transcranial Doppler, xenon-CT, and single-photon emission computed tomography are useful to assess the collateral circulation.17 It should be noted, however, that Mathis et al found that of 192 patients who passed the BOT, 4.7% developed permanent stroke.31 The BOT may not always be possible in the emergency situation, where hemostasis has not been achieved and occlusion intervention may be the only way to save a patient's life.
An alternative to occlusion intervention is placement of a stent graft to seal the injury site and maintain vascular flow. This is, however, technically challenging to place in the tortuous cavernous carotid siphon; stent grafts are also associated with distant migration as well as ICA spasm.8 29 In addition, there is a 4.4% risk of stroke within the first 30 days of stent placement32 as well as requirement of concurrent anticoagulation therapy, which confers its own potential risks.8
Postoperative Considerations
Postoperative care largely involves the prevention of potential complications of carotid artery injury, which include pseudoaneurysm formation and caroticocavernous fistula.2 8 17 25 26 A pseudoaneurysm is a tear through all layers of an artery with persistent flow outside the vessel into a space contained by surrounding tissue.33 Its incidence after carotid artery injury can be as high as 60% and carries with it a risk of rupture for up to 3 months.8 Therefore prompt identification and treatment is required for successful long-term management.
Once hemostasis has been achieved intraoperatively, the patient should be transferred for urgent angiographic investigation to assess the repair and ascertain if further endovascular intervention in required.2 8 26 Angiography should include the external carotid artery if no abnormality is found within the ICA. In addition, the cosurgeons should be available to loosen the packing if localization of the injury site is not possible due to overly tight packing.2 If the immediate postoperative angiogram is normal, then the authors advocate monitoring the patient in the intensive care unit until the packing is removed and another angiogram is performed, usually at 1 week postsurgery. If this is again normal, then the angiogram is repeated at 6 weeks, 3 months, and 1 year.
If pseudoaneurysm is detected, then three main treatment options exist: stent-graft placement, isolated endovascular occlusion of aneurysm lumen, or surgery (bypass or aneurysmal clipping).8 Coil or balloon occlusion has been associated with an increased complication profile as the pseudoaneurysm lacks a wall on which the coil/balloon can sit, and rupture or dissection of the ICA wall can still occur. It is accepted that extracranial/intracranial surgery has a relatively high complication rate, and therefore stent-graft placement in this situation is the safest option. Caroticocavernous fistula, which occurs between the carotid sinus and the cavernous sinus, is treated in much the same way; however, detachable balloons may be used in this setting to occlude the fistula while maintaining parent vessel patency.8 34
Discussion
Endoscopic carotid artery injury is a devastating complication that can induce panic and management paralysis in the surgical team if the surgeons have no experience with this complication and no clear plan of how to manage this event. Review of the English literature reveals several important steps that a surgeon can take to successfully manage this complication. First, optimal preoperative assessment with preoperative planning for such a potential complication is important. Second, skilled operative maneuvers can successfully achieve hemostasis. And third, postoperative assessments and comprehensive management of potential complications will result in the best possible outcome for the patient.
Preoperatively, surgeons must be familiar and competent with the endoscopic approach and anatomy to minimize neurovascular complications.13 14 15 Studious assessment of preoperative CT scans is required, including appreciation of the relationship of the cavernous ICA and the lateral sphenoidal wall,16 17 as well as the potential midline lie of the artery.18 19 Obtainment of MRI or MRA to confirm suspicion of ICA anomalies is also supported as is close assessment of tumor relationship to ICA.8 Factors such as previous radiotherapy, revision surgery, bromocriptine therapy, and acromegaly are helpful to identify the at-risk patient.6 8 22 23 These patients may warrant preoperative assessment of collateral cerebral circulation if their risk is deemed high enough.
Intraoperatively, during a carotid artery injury, emphasis is on controlling the surgical field through the two-surgeon, four-handed technique, to gain vision and better decision making regarding hemostasis.10There are several courses available that allow surgeons to train on animal models so that surgeons may practice the necessary surgical maneuvers that allow successful hemostasis. Having experience in this situation and having a clear surgical plan can be lifesaving for the patient.8 9 10 Nasal packing has been widely described as the method of choice; however, overpacking has been seen to incur its own complications secondary to compression of critical neurovascular structures.8 Use of a crushed muscle patch has been shown to be effective in gaining primary hemostasis and maintains normal vessel characteristics in more than one injury type. However, it has been associated with destabilization and pseudoaneurysm if used as the lone treatment.11 12 In the clinical setting, the authors would advocate for prompt follow-up angiography with endovascular intervention if required.
If the surgical field permits, direct vessel closure techniques such as the U-clip and the T2 aneurysm clip have been shown to be effective in a sheep model of carotid bleeding. The aneurysm clip was not associated with pseudoaneurysm formation; however, placement may influence long-term carotid flow.1112 Reports have also been made on the use of direct suture repair and bipolar.2
If hemostasis cannot be achieved promptly, packing and transfer for angiography and endovascular intervention with balloon, coil, or stent graft is indicated.8 25 28 29 Where possible, assessment of collateral cerebral circulation should be undertaken.17
Postoperative management is focused on the prevention of complications of carotid artery injury, namely pseudoaneurysm and caroticocavernous fistula. After intraoperative intervention, immediate postoperative angiography should be undertaken, followed by repeat investigations at 1 week, 6 weeks, 3 months, and 1 year.8 Preference is given to stent-graft placement over coil or balloon occlusion and surgery due to its comparatively lower complication rate. Detachable balloons, however, may be more appropriate in caroticocavernous fistula.8 34
Disclosures P.J. Wormald receives royalties from Medtronic ENT for instruments designed and is a consultant for Neilmed Pharmaceuticals.
Final Comments
Prevention and management of carotid artery injury is a combination of appropriate patient selection, surgical competency, and teamwork, culminating in the formulation and execution of a surgical plan. In this anxiety-provoking situation, the need for appropriate training cannot be underestimated. In addition to clinical training, targeted vascular workshops utilizing cadaveric and live animal specimens will help surgeons acquire technical expertise as well as skills in teamwork and plan formulation necessary to gain the most favorable outcome for the patient.
References
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Articles from International Archives of Otorhinolaryngology are provided here courtesy of Thieme Medical Publishers
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