Fluorescence imaging to visualize the recurrent laryngeal nerve during thyroidectomy procedures: analysis of 65 cases and 81 nerves.

BACKGROUND: Recurrent laryngeal nerve (RLN) injury after thyroidectomy is relatively common. Locating the RLN prior to thyroid dissection is paramount to avoid injury. We developed a fluorescence imaging system that permits nerve autofluorescence. We aimed to determine the sensitivity and specificity of fluorescence imaging at detecting the RLN relative to thyroid and other background tissue and compared it to white light. METHODS: In this prospective study, 65 patients underwent thyroidectomy from January to April 2022 (16 bilateral thyroid resections) using white and fluorescent light. Fluorescence intensity [relative fluorescence units (RFU)] was recorded for RLN, thyroid, and background. RFU mean, minimum, and maximum values were calculated using Image J software. Thirty randomly selected pairs of white and fluorescent light images were independently reviewed by two examiners to compare RLN detection rate, number of branches, and length and minimum width of nerves visualized. Parametric and nonparametric statistical analysis was performed. RESULTS: All 81 RNLs observed were visualized more clearly under fluorescence (mean intensity, µ = 134.3 RFU) than either thyroid (µ = 33.7, p < 0.001) or background (µ = 14.4, p < 0.001). Forest plots revealed no overlap between RLN intensity and that of either other tissue. Sensitivity and specificity for RLN were 100%. All 30 RLNs and all 45 nerve branches were clearly visualized under fluorescence, versus 17 and 22, respectively, with white light (both p < 0.001). Visible nerve length was 2.5 × as great with fluorescence as with white light (µ = 1.90 vs. 0.76 cm, p < 0.001). CONCLUSIONS: In 65 patients and 81 nerves, RLN detection was markedly and consistently enhanced with autofluorescence neuro-imaging during thyroidectomy, with 100% sensitivity and specificity.

Sensory Evaluation of the Nipple-Areolar Complex Following Primary Breast Augmentation: A Comparison of Incision Approaches.

BACKGROUND: The central inframammary incisional approach for breast augmentation surgery disrupts the fifth anterior intercostal nerve-artery-vein-plexus. The authors hypothesized that preservation of the fifth anterior intercostal neurovascular pedicle might completely preserve nipple-areola complex (NAC) sensitivity after implant breast augmentation. OBJECTIVES: The aim of the study was to analyze if the use of a laterally displaced incision achieves better sensitivity results than the conventional median submammary incision in females who underwent primary breast augmentation surgery. METHODS: A group of 25 female patients (50 breasts) underwent a surgical protocol for primary prepectoral implant breast augmentation with a laterally displaced submammary incision. This group was compared to a similar group of 25 patients (50 breasts) who underwent breast augmentation through a conventional submammary central approach. Sensitivity testing with Semmes-Weinstein monofilaments was performed in both groups preoperatively and on postoperative days 2, 14, and 30, and after 6 months. RESULTS: Both groups were similar in age, BMI, comorbidities, and implant volumes. Preoperatively, all patients reported normal sensory function in both breasts. Postoperatively, in the laterally displaced incision group, sensory function remained normal in NAC areas, whereas in the conventional incision group, all cases presented the same degree of sensitivity diminution at Days 2, 14, and 30 (P = .000). At 6 months, all values were the same as at Day 30. CONCLUSIONS: Preservation of the fifth AIC pedicle resulted in complete preservation of preoperative NAC sensitivity. The laterally placed inframammary incision should be considered for patients undergoing primary prepectoral implant breast augmentation.

Consensus Conference Statement on the General Use of Near-infrared Fluorescence Imaging and Indocyanine Green Guided Surgery: Results of a Modified Delphi Study.

BACKGROUND: In recent decades, the use of near-infrared light and fluorescence-guidance during open and laparoscopic surgery has exponentially expanded across various clinical settings. However, tremendous variability exists in how it is performed. OBJECTIVE: In this first published survey of international experts on fluorescence-guided surgery, we sought to identify areas of consensus and nonconsensus across 4 areas of practice: fundamentals; patient selection/preparation; technical aspects; and effectiveness and safety. METHODS: A Delphi survey was conducted among 19 international experts in fluorescence-guided surgery attending a 1-day consensus meeting in Frankfurt, Germany on September 8th, 2019. Using mobile phones, experts were asked to anonymously vote over 2 rounds of voting, with 70% and 80% set as a priori thresholds for consensus and vote robustness, respectively. RESULTS: Experts from 5 continents reached consensus on 41 of 44 statements, including strong consensus that near-infrared fluorescence-guided surgery is both effective and safe across a broad variety of clinical settings, including the localization of critical anatomical structures like vessels, detection of tumors and sentinel nodes, assessment of tissue perfusion and anastomotic leaks, delineation of segmented organs, and localization of parathyroid glands. Although the minimum and maximum safe effective dose of ICG were felt to be 1 to 2 mg and >10 mg, respectively, there was strong consensus that determining the optimum dose, concentration, route and timing of ICG administration should be an ongoing research focus. CONCLUSIONS: Although fluorescence imaging was almost unanimously perceived to be both effective and safe across a broad range of clinical settings, considerable further research remains necessary to optimize its use.

Nerve autofluorescence in near-ultraviolet light markedly enhances nerve visualization in vivo.

BACKGROUND: During surgery, surgeons must accurately localize nerves to avoid injuring them. Recently, we have discovered that nerves fluoresce in near-ultraviolet light (NUV) light. The aims of the current study were to determine the extent to which nerves fluoresce more brightly than background and vascular structures in NUV light, and identify the NUV intensity at which nerves are most distinguishable from other tissues. METHODS: We exposed sciatic nerves within the posterior thigh in five 250-300 gm Wistar rats, then observed them at four different NUV intensity levels: 20%, 35%, 50%, and 100%. Brightness of fluorescence was measured by fluorescence spectroscopy, quantified as a fluorescence score using Image-J software, and statistically compared between nerves, background, and both an artery and vein by unpaired Student's t tests with Bonferroni adjustment to accommodate multiple comparisons. Sensitivity, specificity, and accuracy were calculated for each NUV intensity. RESULTS: At 20, 35, 50, and 100% NUV intensity, fluorescence scores for nerves versus background tissues were 117.4 versus 40.0, 225.8 versus 88.0, 250.6 versus 121.4, and 252.8 versus 169.4, respectively (all p < 0.001). Fluorescence scores plateaued at 50% NUV intensity for nerves, but continued to rise for background. At 35%, 50%, and 100% NUV intensity, a fluorescence score of 200 was 100% sensitive, specific, and accurate identifying nerves. At 100 NUV intensity, artery and vein scores were 61.8 and 60.0, both dramatically lower than for nerves (p < 0.001). CONCLUSIONS: At all NUV intensities ≥ 35%, a fluorescence score of 200 is 100% accurate distinguishing nerves from other anatomical structures in vivo.

Nerve autofluorescence under near-ultraviolet light: cutting-edge technology for intra-operative neural tissue visualization in 17 patients.

BACKGROUND: Nerve visualization and the identification of other neural tissues during surgery is crucial for numerous reasons, including the prevention of iatrogenic nerve and neural structure injury and facilitation of nerve repair. However, current methods of intra-operative nerve detection are generally expensive, unproven, and/or technically challenging. Recently, we have documented, in both in vivo animal models and ex vivo human tissue, that nerves autofluorescence when viewed in near-ultraviolet light (NUV). In this paper, we describe our use of nerve autofluorescence to facilitate the visualization of nerves and other neural tissues intra-operatively in 17 patients undergoing a range of surgical procedures. METHODS: Employing the same prototype axon imaging system previously documented to markedly enhance nerve visualization in both in vivo animal and ex vivo human models, surgical fields were observed in 17 patients under both white and NUV light during parotid tumor resection (n = 3), thyroid tumor resection (n = 7), and surgery for peripheral nerve and spinal tumors and injury (n = 7). RESULTS: In all 17 patients, the intra-operative use of the imaging system both was feasible and markedly enhanced the localization of all neural tissues throughout their course within the surgical field. All 17 procedures were successful and devoid of any peri-operative complications or post-operative neurological deficits. CONCLUSIONS: Intra-operatively visualizing auto-fluorescent peripheral nerves and other neural tissues under NUV light is feasible in human patients across a range of clinical scenarios and appears to appreciably enhance nerve and other neural tissue visualization. Controlled studies to explore this technology further are needed.

Understanding intraoperative fluorescent cholangiography: ten steps for an effective and successful procedure.

BACKGROUND: Common bile duct injuries (BDI) during laparoscopic cholecystectomy (LC) continue to be the source of morbidity and mortality. The reason for BDI is mostly related to the misidentification of the extrahepatic bile duct structures and the anatomic variability. Near-infrared fluorescent cholangiography (NIFC) has proven to enhance visualization of extrahepatic biliary structures during LCs. The purpose of this study was to describe the most important steps in the performance of NIFC. METHODS: In accordance to the most current surgical practice of LC at our institution, a consensus was achieved on the most relevant steps to be followed when utilizing NIFC. Dose of indocyanine green (ICG), time of administration, and identification of critical structures were previously determined based on prospective and randomized controlled studies performed at CCF. RESULTS: The ten steps identified as critical when performing NIFC during LC are preoperative administration of ICG, exposure of the hepatoduodenal ligament, initial anatomical evaluation, identification of the cystic duct and common bile duct junction, the cystic duct and its junction to the gallbladder, the CHD, the common bile duct, accessory ducts, cystic artery and, time-out and identification of Calot's triangle, and evaluation of the liver bed. CONCLUSIONS: Routine use of NIFC is a useful diagnostic tool to better visualize the extrahepatic biliary structures during LC. The implementation of specific standardized steps might provide the surgeon with a better algorithm to use this technology and consequently reduce the incidence of BDI.

Nerve spectroscopy: understanding peripheral nerve autofluorescence through photodynamics.

BACKGROUND: Being able to accurately identify sensory and motor nerves is crucial during surgical procedures to prevent nerve injury. We aimed to (1) evaluate the feasibility of performing peripheral human nerve visualization utilizing nerves' own autofluorescence in an ex-vivo model; (2) compare the effect of three different nerve fiber fixation methods on the intensity of fluorescence, indicated as the intensity ratio; and (3) similarly compare three different excitation ranges. METHODS: Samples from various human peripheral nerves were selected postoperatively. Nerve fibers were divided into three groups: Group A nerve fibers were washed with a physiologic solution; Group B nerve fibers were fixated with formaldehyde for 6 h first, and then washed with a physiologic solution; Group C nerve fibers were fixated with formaldehyde for six hours, but not washed afterwards. An Olympus IX83 inverted microscope was used for close-up image evaluation. Nerve fibers were exposed to white-light wavelength spectrums for a specific time frame prior to visualization under three different filters-Filter 1-LF405-B-OMF Semrock; Filter 2-U-MGFP; Filter 3-U-MRFPHQ Olympus, with excitation ranges of 390-440, 460-480, and 535-555, respectively. The fluorescence intensity of all images was subsequently analyzed using Image-J Software, and results compared by analysis of variance (ANOVA). RESULTS: The intensity ratios observed with Filter 1 failed to distinguish the different nerve fiber groups (p = 0.39). Conversely, the intensity ratios seen under Filters 2 and 3 varied significantly between the three nerve-fiber groups (p = 0.021, p = 0.030, respectively). The overall intensity of measurements was greater with Filter 1 than Filter 3 (p < 0.05); however, all nerves were well visualized by all filters. CONCLUSION: The current results on ex vivo peripheral nerve fiber autofluorescence suggest that peripheral nerve fiber autofluorescence intensity does not greatly depend upon the excitation wavelength or fixation methods used in an ex vivo setting. Implications for future nerve-sparing surgery are discussed.

Incisionless fluorescent cholangiography (IFC): a pilot survey of surgeons on procedural familiarity, practices, and perceptions.

BACKGROUND: Incisionless fluorescent cholangiography (IFC) has recently been proven feasible, safe, and efficacious as an intraoperative procedure to help identify extrahepatic bile ducts during laparoscopic cholecystectomies (LC). We conducted a pilot survey of 51 surgeons attending an international conference who perform endoscopic cholecystectomies to identify their typical LC practices, and perceptions of IFC. METHODS: An international panel of ten IFC experts, all with > 500 prior IFC procedures and related research publications, convened during the 4th International Congress of Fluorescence-Guided Surgery in Boca Raton, Florida in February 2017. The panel was charged with developing questions about LC practices and experience with IFC, and perceptions regarding its advantages, barriers to use, and indications. These questions then were asked to other congress attendees during one of the didactic sessions using an online polling application. Attendees, who ranged from zero to considerable experience performing IFC, accessed the survey via their portable devices. RESULTS: Of the 51 survey participants, 51% were from North America; 77% identified themselves as general/minimally invasive surgeons, and roughly 60% performed under 50 cholecystectomies/year. Only 12% performed routine intraoperative cholangiography (IOC), while 72.3% routinely performed critical safety reviews. Thirty-five percent estimated that their institution's laparoscopic-to-open surgery conversion rate was > 1% during LC. Roughly 95% of respondents felt that surgeons should have access to a noninvasive method for evaluating extrahepatic biliary structures; 84% felt that the most advantageous characteristic of IFC is the lack of any biliary-tree incision; and 93.3% felt that IFC would have considerable educational value in surgical training programs; and 78% felt that any surgeon who performs LC could benefit. CONCLUSIONS: Surgeons who participated in our survey overwhelmingly recommended the routine use of IFC during laparoscopic cholecystectomy as a complimentary imaging technique. Prospective randomized clinical trials remain necessary to determine whether IFC reduces the incidence of bile duct injuries and other LC complications.

Randomized Trial of Near-infrared Incisionless Fluorescent Cholangiography.

BACKGROUND: Incisionless near-infrared fluorescent cholangiography (NIFC) is emerging as a promising tool to enhance the visualization of extrahepatic biliary structures during laparoscopic cholecystectomies. METHODS: We conducted a single-blind, randomized, 2-arm trial comparing the efficacy of NIFC (n = 321) versus white light (WL) alone (n = 318) during laparoscopic cholecystectomy. Using the KARL STORZ Image1 S imaging system with OPAL1 technology for NIR/ICG imaging, we evaluated the detection rate for 7 biliary structures-cystic duct (CD), right hepatic duct (RHD), common hepatic duct, common bile duct, cystic common bile duct junction, cystic gallbladder junction (CGJ), and accessory ducts -before and after surgical dissection. Secondary calculations included multivariable analysis for predictors of structure visualization and comparing intergroup biliary duct injury rates. RESULTS: Predissection detection rates were significantly superior in the NIFC group for all 7 biliary structures, ranging from 9.1% versus 2.9% to 66.6% versus 36.6% for the RHD and CD, respectively, with odds ratios ranging from 2.3 (95% CI 1.6-3.2) for the CGJ to 3.6 (1.6-9.3) for the RHD. After dissection, similar intergroup differences were observed for all structures except CD and CGJ, for which no differences were observed. Significant odds ratios ranged from 2.4 (1.7-3.5) for the common hepatic duct to 3.3 (1.3-10.4) for accessory ducts. Increased body mass index was associated with reduced detection of most structures in both groups, especially before dissection. Only 2 patients, both in the WL group, sustained a biliary duct injury. CONCLUSIONS: In a randomized controlled trial, NIFC was statistically superior to WL alone visualizing extrahepatic biliary structures during laparoscopic cholecystectomy. REGISTRATION NUMBER: NCT02702843.

Smartphone Application as an Education Platform in Hepato-Pancreato-Biliary Surgery.

Background. There are no data to assess the need for smartphone applications (SA) as an educational tool in hepato-pancreato-biliary (HPB) surgery. The primary objective of this study was to assess if SA can be used as an educational tool in HPB surgery. The secondary objective was to assess if SA can help as a decision-making tool for fellowship applicants in HPB surgery. Methods. A preapproved questionnaire was e-mailed by International Hepato-Pancreato-Biliary Association to all its 2350 members. Results. Two hundred seventy-one surgeons responded to the survey. Eight were excluded for incomplete data. A total of 48.7% of responders were between 28 and 43 years old (generation X) and 45.2% between 44 and 62 years old (baby boomers). A total of 37.6% of the responders considered SA as an effective method to teach future trainees, and there were slightly higher odds of choosing SA as a teaching tool if the responder considered themselves as an innovator (odds ratio: 2.24). A total of 87.8% of the responders believe that SA in HPB surgery can be directed toward surgical trainees' education, and 91.6% believed SA can be directed toward a fellow. Ninety-five percent of the responders believed that SA in HPB surgery can possibly help a future applicant to choose an HPB fellowship program. Conclusion. SA can complement other teaching techniques and educational tools in HPB surgery. In addition, it can potentially be used as a platform for HPB surgery fellowship by helping in making a decision regarding appropriate fellowship programs.

Detection of Parathyroid Autofluorescence Using Near-Infrared Imaging: A Multicenter Analysis of Concordance Between Different Surgeons.

BACKGROUND: Parathyroid glands (PGs) exhibit autofluorescence (AF) when excited by near-infrared laser. This multicenter study aims to analyze how this imaging could facilitate the detection of PGs during thyroidectomy and parathyroidectomy procedures. METHODS: This was a retrospective Institutional Review Board-approved analysis of prospectively collected data at three centers. Near-infrared fluorescence imaging (NIFI) was used to detect AF from PGs during thyroidectomy and parathyroidectomy procedures. Logistic regression analysis was performed to assess the utility of NIFI to identify PGs and concordance at these centers. RESULTS: Overall, 210 patients underwent total thyroidectomy (n = 95), thyroid lobectomy (n = 41), and parathyroidectomy (n = 74) (n = 70 per center). Using NIFI, AF was detected from 98% of visually identified PGs. Upon initial exploration, 46% of PGs were not visible to the naked eye due to coverage by soft tissue, but AF from these glands could be detected by NIFI without any further dissection. Overall, a median of one PG per patient was detected by NIFI in this fashion before being identified visually (p = nonsignificant between centers). On logistic regression, smaller PGs were more likely to be missed visually, but localized by AF on NIFI (odds ratio with increasing size, 0.91; p = 0.02). CONCLUSIONS: In our experience, NIFI facilitated PG identification by detecting their AF, before conventional recognition by the surgeon, in 37-67% of the time. Despite the variability in this rate across centers, there was a concordance in detecting AF from 97 to 99% of the PGs using NIFI. We suggest the incorporation of AF on NIFI alongside conventional visual cues to aid identification of PGs during neck operations.

Intraoperative Ureter Visualization Using a Novel Near-Infrared Fluorescent Dye.

Ureters can be accidentally severed during pelvic surgeries, significantly prolonging the times in the operating room to allow for complete repair of damaged ureters and leading to significant morbidities associated with consequent ureter obstruction and possible kidney dysfunction. In an effort to prevent these complications, light-emitting stents and urine-excreted dyes have been introduced to illuminate the ureter during surgery. However, problems with mechanical insertion, ureter spasm, image contrast, and localized injection have limited interest in their clinical applications. We report here the synthesis and characterization of a new near-infrared (NIR) fluorescent dye (UreterGlow) that can be injected systemically but is excreted primarily through the renal system, allowing ureter imaging with an NIR fluorescence camera. Following intravenous injection of 0.1 mg/kg UreterGlow, we have monitored the flow of UreterGlow through the proximal, medial, and distal segments of the ureter. The timing of ureter visualization was calculated from the time of injection of the drug. The null hypothesis was that "Visualization of the ureter in pigs is possible 60 min after administration of UreterGlow using an NIR camera". UreterGlow displayed excitation and emission maxima of λex = 800 nm and λem = 830 nm in phosphate buffered saline, pH 7.4, and could be imaged in the urinary tract in mice. Shortly after injection of UreterGlow into Yorkshire pigs, peristalsis of the ureter could be observed. The distal ureter could be visualized under NIR illumination after 60 min with constant fluorescence in all five pigs for >2 h. The same ureters could not be seen using visible light ( X2, p = 0.0001). Because both excitation and emission of UreterGlow occurs at >30 nm longer wavelength than most tumor-imaging fluorescent dyes, it should be possible to distinguish ureter fluorescence from tumor fluorescence with this dye.

Increased identification of parathyroid glands using near infrared light during thyroid and parathyroid surgery.

BACKGROUND: Parathyroid gland (PG) identification during thyroid and parathyroid surgery is challenging. Accidental parathyroidectomy increases the rate of postoperative hypocalcaemia. Recently, autofluorescence with near infrared light (NIRL) has been described for PG visualization. The aim of this study is to analyze the increased rate of visualization of PGs with the use of NIRL compared to white light (WL). MATERIALS AND METHODS: All patients undergoing thyroid and parathyroid surgery were included in this study. PGs were identified with both NIRL and WL by experienced head and neck surgeons. The number of PGs identified with NIRL and WL were compared. The identification of PGs was correlated to age, sex, and histopathological diagnosis. RESULTS: Seventy-four patients were included in the study. The mean age was 48.4 (SD ±13.5) years old. Mean PG fluorescence intensity (47.60) was significantly higher compared to the thyroid gland (22.32) and background (9.27) (p < 0.0001). The mean number of PGs identified with NIRL and WL were 3.7 and 2.5 PG, respectively (p < 0.001). The difference in the number of PGs identified with NIRL and WL and fluorescence intensity was not related to age, sex, or histopathological diagnosis, with the exception of the diagnosis of thyroiditis, in which there was a significant increase in the number of PGs visualized with NIRL (p = 0.026). CONCLUSION: The use of NIRL for PG visualization significantly increased the number of PGs identified during thyroid and parathyroid surgery, and the differences in fluorescent intensity among PGs, thyroid glands, and background were not affected by age, sex, and histopathological diagnosis.

Fluorescent incisionless cholangiography as a teaching tool for identification of Calot's triangle.

BACKGROUND: Intraoperative incisionless fluorescent cholangiogram (IOIFC) has been demonstrated to be a useful tool to increase the visualization of Calot's triangle. This study evaluates the identification of extrahepatic biliary structures with IOIFC by medical students and surgery residents. METHODS: Two pictures were taken, one with xenon light and one with near-infrared (NIR) light, at the same stage during dissection of Calot's triangle in ten different cases of laparoscopic cholecystectomy (LC). All twenty pictures were organized in a random fashion to remove any imagery bias. Twenty students and twenty residents were asked to identify the biliary anatomy. RESULTS: Medical students were able to accurately identify the cystic duct on an average 33.8 % under the xenon light versus 86 % under NIR light (p = 0.0001), the common hepatic duct (CHD) on an average 19 % under the xenon light versus 88.5 % under NIR light (p = 0.0001), and the junction on an average 24 % under xenon light versus 80.5 % under NIR light (p = 0.0001). Surgery residents were able to accurately identify the cystic duct on an average 40 % under the xenon light versus 99 % under NIR light (p = 0.0001), the CHD on an average 35 % under the xenon light versus 96 % under NIR light (p = 0.0001), and the junction on an average 24 % under the xenon light versus 95.5 % under NIR light (p = 0.0001). CONCLUSIONS: IOIFC increases the visualization of Calot's triangle structures when compared to xenon light. IOIFC may be a useful teaching tool in residency programs to teach LC.

The relationship between intracranial pressure and obesity: an ultrasonographic evaluation of the optic nerve.

BACKGROUND: Measurements of optic nerve sheath diameter (ONSD) with noninvasive ocular ultrasonography have been shown to be accurate in determining increased intracranial pressure. Obesity is associated with chronic increases in intraabdominal pressure that could consequently result in intracranial hypertension. By utilizing ONSD ultrasonographic measurements, we compare the difference that may exist between obese and non-obese patients. STUDY DESIGN: We prospectively collected data from patients who underwent laparoscopic procedures in the supine position between July 2013 and March 2014. Ophthalmic pathology was not present in any patient. Ultrasonographic measurement of the ONSD was obtained sagittally with a 12-MHz transducer 3 mm from its origin. The measurements were taken at 0, 15, and 30 min, and at the end of surgery. RESULTS: There were 62 subjects, 28 females (45.2 %) and 34 males (54.8 %), with a mean age of 44.22 ± 10.44 years (range 23-66). Forty-eight percent of patients were non-obese, and 52 % of patients were obese. The mean body mass index was 30.70 ± 7.61 kg/m(2) (range 20.0-59.5). The mean ONSD of non-obese and obese patients was 4.7 and 5.5 mm at baseline (p = 0.01), 5.4 and 6.2 mm at 15 min (p = 0.01), 5.8 and 6.6 mm at 30 min (p = 0.01), and 5.1 and 5.7 mm after deflation of pneumoperitoneum (p = 0.03), respectively. CONCLUSIONS: Utilizing a noninvasive method to measure the ONSD, a chronic increase in intracranial pressure in obese patients was demonstrated. The increase in the ONSD during laparoscopic procedures reflects a temporary increase in the intracranial pressure from baseline.

Impact of controlled intraabdominal pressure on the optic nerve sheath diameter during laparoscopic procedures.

BACKGROUND: Acute elevations of intraabdominal pressure (IAP) are seen in many clinical scenarios with a consequent elevation in intracranial pressure (ICP). With the optic nerve sheath (ONS) being a part of the dura mater and the optic nerve surrounded by cerebral spinal fluid, a change in pressure within the subarachnoid space would be detected by ultrasonography, and invasive methods could be avoided. The study objective was to evaluate ultrasonographic modifications observed on the optic nerve sheath diameter during acute elevations of IAP in patients undergoing laparoscopic procedures. STUDY DESIGN: We prospectively collected data from patients who underwent laparoscopic procedures between July and August 2013. The optic nerve sheath diameter was measured sagittally with a 12-MHz transducer. The measurements were obtained at baseline, 15 and 30 min, and at the end of surgery. RESULTS: There were 16 females (36.4%) and 28 males (63.6%), with a mean age of 44.22 ± 10.44 years (range 23-66) and body mass index of 29.45 ± 6.53 kg/m(2) (range 21-39). The mean optic nerve sheath diameter was 4.8 ± 1.0 mm at baseline, 5.5 ± 1.1 mm at 15 min, 5.9 ± 1.0 mm at 30 min, and 5.1 ± 1.2 mm after deflation of pneumoperitoneum. The diameter increased significantly at 15 min by a median of 0.6 mm (interquartile range 0.3, 0.8; p < 0.0001) and at 30 min by a median of 1.0 mm (interquartile range 0.7, 1.4; p < 0.0001), returning close to baseline after surgery. CONCLUSION: The acute elevation in IAP during laparoscopy significantly increased the optic nerve sheath diameter. The changes in the ONSD reflect a temporary and reversible increase in the ICP due to the acute elevation of IAP.

Unidirectional barbed sutures as a novel technique for laparoscopic ventral hernia repair.

BACKGROUND: Incisional hernias remain a significant complication of abdominal surgeries. Primary closure of the hernia defect has been suggested to improve long-term abdominal wall function. However, this can be technically challenging and time consuming. This study describes laparoscopic use of non-absorbable barbed sutures in primary closure of hernia defects in addition to intraperitoneal mesh. METHODS: Patients who underwent laparoscopic primary ventral hernia repair with mesh were prospectively reviewed. Two groups were defined: Operations performed with barbed sutures for primary closure in addition to mesh and operations with only mesh without defect repair. The surgical technique involved running the hernia defect with a 2-polypropylene non-absorbable unidirectional barbed suture and subsequently fixing the mesh intraperitoneally with tacks. In both groups, a single transfascial centering suture was also utilized. RESULTS: Twenty-eight cases with barbed suture and mesh reinforcement and 29 cases with mesh-only were identified. The average dimensions of the ventral hernia defects were 57.8 (6-187) and 44.6 cm(2) (9-156) in the barbed suture with mesh and mesh-only group, respectively, p = 0.23. Median operating time was 78 min (range 35-187 min) in the barbed suture with mesh group versus 62 min (34-155 min) in the mesh-only group, p = 0.44. The median suturing time of closing the ventral hernia defect was 16 min (11-24 min). There were no differences in the pain scores. Mean follow-up for both groups was 8.2 ± 3.6 months (1-17 months) with one hernia recurrence in the mesh-only group, p = 0.41. CONCLUSIONS: The barbed suture closure system could be used for rapid and effective primary defect closure in laparoscopic ventral hernia repair in addition to intraperitoneal mesh placement. No significant difference in operating time was detected when compared to the mesh-only approach. Further evidence to support these findings and longer follow-up periods is warranted to evaluate short- and long-term complications.

Routine use of fluorescent incisionless cholangiography as a new imaging modality during laparoscopic cholecystectomy.

BACKGROUND: Intraoperative incisionless fluorescent cholangiography (IOIFC) has been described to identify extrahepatic biliary anatomy. Potential advantages of the routine use of intraoperative incisionless fluorescent cholangiography were evaluated in a consecutive series of cases. METHODS: A total of 45 patients undergoing laparoscopic cholecystectomy between January and July 2013 were consented and included in this study. We analyzed a prospectively collected database for feasibility, cost, time, usefulness, teaching tool, safety, learning curve, X-ray exposure, complexity, and real-time surgery of IOIFC. A single dose of 0.05 mg/kg of Indocyanine green was administered prior to surgery. During the procedure, a laparoscopic fluorescence system was used. RESULTS: IOIFC could be performed in all 45 patients, whereas intraoperative cholangiography could be performed in 42 (93 %). Individual median cost of performing IOFC was cheaper than IOC (13.97 ± 4.3 vs 778.43 ± 0.4 USD) per patient, p = 0.0001). IOFC was faster than IOC (0.71 ± 0.26 vs 7.15 ± 3.76 minutes, p < 0.0001). The cystic duct was identified by IOFC in 44 out of 45 patients (97.77 %). CONCLUSION: IOIFC appears to be a feasible, low-cost, expeditious, useful, and effective imaging modality when performing LC. It is safe, easy to perform and interpret, and does not require a learning curve or X-ray. It can be used for real time surgery to delineate the extrahepatic biliary structures.

Technical description and feasibility of laparoscopic adrenal contouring using fluorescence imaging.

BACKGROUND: Identification of adrenal glands from the surrounding structures during laparoscopic surgery can be challenging especially in obese individuals. This can increase the chances for hemorrhage and conversion to open surgery. We present the first report of fluorescent infrared visualization of the adrenal glands in a large animal model. METHODS: Five adult Yorkshire pigs were utilized for the study, in compliance with the animal study regulations. After an intravenous bolus administration of 3 mL of indocyanine green (ICG), visualization was performed with a xenon/infrared light source and a laparoscope with a charge-coupled filter device. Activation of the device was done with a foot pedal. Images were analyzed using histogram software and the difference of enhancement was statistically analyzed using unpaired two-tailed t test. RESULTS: The right adrenal glands were visualized in all five animals immediately after administering ICG. Fluorescence facilitated demarcation of adrenal gland tissue from surrounding adipose tissue. Peritoneum and fat was visualized in black color. Adrenal enhancement lasted for 4 h in all cases. The mean value for adrenal fluorescence using histogram count was 71.75 pixels, and for adrenal xenon was 168.87 pixels (p = 0.0002; 95 % CI -130.93 to -0.63). The mean value for fat fluorescence using histogram count was 5.54 pixels and fat xenon was 187.15 pixels (p = 0.0001; 95 % CI -199.39 to -163.82). Although there was no significant difference between adrenal and fat enhancement with xenon light (p = 0.24; 95 % CI -15.53 to 52.09), the difference became significant between adrenal and fat fluorescence (p = 0.0001; 95 % CI 48.51-83.9). CONCLUSION: Fluorescence imaging appears to be a feasible and easy method to differentiate adrenal glands from the surrounding tissue in a large animal model. Further studies are necessary to investigate the real application of this method during laparoscopic adrenalectomy in humans.

Novel technique for identification of ureters using sodium fluorescein.

BACKGROUND: The unique property of sodium fluorescein has made it ideal for use in medical applications such as diagnostic ophthalmology and intravenous angiography. It is mainly excreted via the renal system and although extensively used in these diagnostic applications, it has not been widely used to aid in the visualization of the ureters. It is possible to visualize the urinary tract by shining a source of light and studying the fluorescence using a special filter. The goal of our study was to assess the real-time visualization of ureters using intravenous sodium fluorescein under the stimulus of a 530 nm wavelength light. MATERIALS AND METHODS: Nine 250 gm Wister rats were given an intravenous dose of 0.01 ml of sodium fluorescein. A laparotomy was immediately performed following the administration of dye. Anesthesia was performed with an intraperitoneal dose of ketamine-xylazine. The retroperitoneum was exposed and observed under an alternating white xenon and a 530 nm excitation light with an objective to visualize the organs captured within the fluorescence of the compound (sodium fluorescein). RESULTS: Under xenon light, the location of the kidneys and urinary bladder were visualized, but not the ureters. The light was then changed to a 530 nm wavelength mode when the location and orientation of the ureters was visualized along with the peristaltic movements. Fluorescence visualization of the ureters was noted 5-10 min following kidney visualization. In addition, the vascular structures in close proximity to the ureters were also visualized. None of the rats underwent any retroperitoneal dissection, and in one case, partial mobilization of a kidney was undertaken. All rats were euthanized at the completion of the procedure. CONCLUSION: Intravenous administration of sodium fluorescein enables fluorescence visualization of the ureters in a rat model, after activation with a 530 nm light transmitter.