Indocyanine green:The guide to safer and more effective surgery

In this editorial we comment on the article by Kalayarasan and co-workers published in the recent issue of the World Journal of Gastrointestinal Surgery.The authors present an interesting review on the use of indocyanine green fluo-rescence in different aspects of abdominal surgery.They also highlight future perspectives of the use of indocyanine green in mini-invasive surgery.Indo-cyanine green,used for fluorescence imaging,has been approved by the Food and Drug Administration and is safe for use in humans.It can be administered in-travenously or intra-arterially.Since its advent,there have been several advance-ments in the applications of indocyanine green,especially in the surgical field,such as intraoperative mapping and biopsy of sentinel lymph node,measurement of hepatic function prior to resection,in neurosurgical cases to detect vascular anomalies,in cardiovascular cases for patency and assessment of vascular ab-normalities,in predicting healing following amputations,in helping visualization of hepatobiliary anatomy and blood vessels,in reconstructive surgery,to assess flap viability and for the evaluation of tissue perfusion following major trauma and burns.For these reasons,the intraoperative use of indocyanine green has become common in a variety of surgical specialties and transplant surgery.Co-lorectal surgery has just lately begun to adopt this technique,particularly for perfusion visualization to prevent anastomotic leakage.The regular use of in-docyanine green coupled with fluorescence angiography has recently been pro-posed as a feasible tool to help improve patient outcomes.Using the best available data,it has been shown that routine use of indocyanine green in colorectal surgery reduces the rates of anastomotic leak.The use of indocyanine green is proven to be safe,feasible,and effective in both elective and emergency scenarios.However,additional robust evidence from larger-scale,high-quality studies is essential before incorporating indocyanine green guided surgery into standard practice.

Relevance of ADAMTS13 to liver transplantation and surgery

A disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13(ADAMTS13) specifically cleaves unusually-large von Willebrand factor(VWF) multimers under high shear stress,and down-regulates VWF function to form platelet thrombi.Deficiency of plasma ADAMTS13 activity induces a life-threatening systemic disease,termed thrombotic microangiopathy(TMA) including thrombotic thrombocytopenic purpura(TTP).Children with advanced biliary cirrhosis due to congenital biliary atresia sometimes showed pathological features of TMA,with a concomitant decrease of plasma ADAMTS13 activity.Disappearance of their clinical findings of TTP after successful liver transplantation suggested that the liver is a major organ producing plasma ADAMTS13.In situ hybridization analysis showed that ADAMTS13 was produced by hepatic stellate cells.Subsequently,it was found that ADADTS13 was not merely responsible to development of TMA and TTP,but also related to some kinds of liver dysfunction after liver transplantation.Ischemia-reperfusion injury and acute rejection in liver transplant recipients were often associated with marked decrease of ADAMTS13 and concomitant formation of unusually large VWF multimers without findings of TMA/TTP.The similar phenomenon was observed also in patients who underwent hepatectomy for liver tumors.Imbalance between ADAMTS13 and VWF in the hepatic sinusoid might cause liver damage due to microcirculatory disturbance.It can be called as "local TTP like mechanism" which plays a crucial role in liver dysfunction after liver transplantation and surgery.

Drugs used for pain management in gastrointestinal surgery and their implications

Pain is the predominant symptom troubling patients.Pain management is one of the most important aspects in the management of surgical patients leading to early recovery from surgical procedures or in patients with chronic diseases or malignancy.Various groups of drugs are used for dealing with this;however,they have their own implications in the form of adverse effects and dependence.In this article,we review the concerns of different pain-relieving medicines used postoperatively in gastrointestinal surgery and for malignant and chronic diseases.

Impact of frailty on short-term postoperative outcomes in patients undergoing colorectal cancer surgery:A systematic review and meta-analysis

BACKGROUND Colorectal cancer is a major global health challenge that predominantly affects older people.Surgical management,despite advancements,requires careful consideration of preoperative patient status for optimal outcomes.AIM To summarize existing evidence on the association of frailty with short-term postoperative outcomes in patients undergoing colorectal cancer surgery.METHODS A literature search was conducted using PubMed,EMBASE and Scopus databases for observational studies in adult patients aged≥18 years undergoing planned or elective colorectal surgery for primary carcinoma and/or secondary metastasis.Only studies that conducted frailty assessment using recognized frailty assess-ment tools and had a comparator group,comprising nonfrail patients,were included.Pooled effect sizes were reported as weighted mean difference or relative risk(RR)with 95%confidence intervals(CIs).RESULTS A total of 24 studies were included.Compared with nonfrail patients,frailty was associated with an increased risk of mortality at 30 d(RR:1.99,95%CI:1.47-2.69),at 90 d(RR:4.76,95%CI:1.56-14.6)and at 1 year(RR:5.73,95%CI:2.74-12.0)of follow up.Frail patients had an increased risk of any complications(RR:1.81,95%CI:1.57-2.10)as well as major complications(Clavien-Dindo classification grade≥III)(RR:2.87,95%CI:1.65-4.99)compared with the control group.The risk of reoperation(RR:1.18,95%CI:1.07-1.31),readmission(RR:1.70,95%CI:1.36-2.12),need for blood transfusion(RR:1.67,95%CI:1.52-1.85),wound complications(RR:1.49,95%CI:1.11-1.99),delirium(RR:4.60,95%CI:2.31-9.16),risk of prolonged hospitalization(RR:2.09,95%CI:1.22-3.60)and discharge to a skilled nursing facility or rehabilitation center(RR:3.19,95%CI:2.0-5.08)was all higher in frail patients.CONCLUSION Frailty in colorectal cancer surgery patients was associated with more complications,longer hospital stays,higher reoperation risk,and increased mortality.Integrating frailty assessment appears crucial for tailored surgical management.

Enhanced recovery after surgery:Progress in adapted pathways for implementation in standard and emerging surgical settings

The concept of enhanced recovery after surgery(ERAS)has been practiced for decades and has been implemented in numerous surgical specialties.ERAS is a global surgical quality improvement initiative,and it is an element in the field of perioperative care.ERAS had shown significant clinical outcomes,patientreported satisfaction,and improvements in medical service cost.ERAS has been developed for specific surgical procedures,but with the fast progress of newly introduced surgical procedures,the original ERAS have been developed and modified.Recently appearing Topics and future research trends encompass ERAS protocols for other types of surgery and the enhancement of perioperative status,including but not limited to pediatric surgery,laparoscopic and robotic assisted surgery,bariatric surgery,thoracic surgery,and renal transplantation.The elements and pathways of ERAS have been developed with the introduction of up-to-date methodologies in the pre-operative,operative,and post-operative pathways.ERAS costs are higher than traditional care,but the patient’s clinical outcome and satisfaction are higher.ERAS is in progress in the fields of anesthetic tasks,pediatric surgery,and organ transplantation.Although ERAS has shown significant clinical outcomes,there are needs to modify the protocol for specific cases,hospital facilities,resources,and nurses training on elements of ERAS.Several challenges and limitations exist in the implementation of ERAS that deserve consideration,it includes:Frailty,maximizing nutrition,prehabilitation,treating preoperative anemia,and enhancing ERAS adoption globally are all included.

Quality of life and functional capacity in patients after cardiac surgery intensive care unit

Coronary heart disease and aortic stenosis are prevalent cardiovascular diseases worldwide,leading to morbidity and mortality.Coronary artery bypass grafting(CABG)and surgical aortic valve replacement(SAVR)have therapeutic benefits,including improved postoperative quality of life(QoL)and enhanced patient functional capacity which are key indicators of cardiac surgery outcome.In this article,we review the latest studies of QoL outcomes and functional capacity in patients who underwent cardiac surgery.Many standardized instruments are used to evaluate QoL and functional conditions.Preoperative health status,age,length of intensive care unit stay,operative risk,type of procedure,and other pre-,intra-,and postoperative factors affect postoperative QoL.Elderly patients experience impaired physical status soon after cardiac surgery,but it improves in the following period.CABG and SAVR are associated with increases of physical and mental health and functional capacity in the immediate postoperative and the long long-term.Cardiac rehabilitation improves patient functional capacity,QoL,and frailty following cardiac surgery.

Exploring the landscape of minimally invasive pancreatic surgery: Progress, challenges, and future directions

Minimally invasive surgery(MI)has become the standard of care for many surgical procedures aimed at reducing the burden on patients.However,its adoption in pancreatic surgery(PS)has been limited by the pancreas’s unique location and the complexity of the dissection and reconstruction phases.These factors continue to contribute to PS having one of the highest morbidity and mortality rates in general surgery.Despite a rough start,MIPS has gained widespread acceptance in clinical practice recently.Robust evidence supports MI distal pancreatectomy safety,even in oncological cases,indicating its potential superiority over open surgery.However,definitive evidence of MI pancre-aticoduodenectomy(MIPD)feasibility and safety,particularly for malignant lesions,is still lacking.Nonetheless,reports from high-volume centers are emer-ging,suggesting outcomes comparable to those of the open approach.The robotic PS increasing adoption,facilitated by the wider availability of robotic platforms,may further facilitate the transition to MIPD by overcoming the technical con-straints associated with laparoscopy and accelerating the learning curve.Alth-ough the MIPS implementation process cannot be stopped in this evolving world,ensuring patient safety through strict outcome monitoring is critical.Investing in younger surgeons with structured and recognized training programs can promote safe expansion.

Combined Carbon Dioxide Laser Lateral Canthotomy and Femtosecond Laser-Assisted Cataract Surgery

Purpose: The purpose of this study was to evaluate a new procedure aimed at lengthening the palpebral fissure to facilitate femtosecond laser-assisted cataract surgery in patients with small eyes. Method: A quick procedure using the CO2 laser was adapted for patients with small eyes undergoing laser-assisted cataract surgery using the Catalys system. The UniPulse CO2 laser (Nidek) was used for laser lateral canthotomy on patients with small palpebral fissures to allow fitting of the Liquid OpticTM Interface eyepiece. Results: Lateral canthotomies were performed on 19 women and 7 men (ages ranged from 45 to 93 years) with lower eyelid lengths equal to or shorter than 32 mm who then underwent femtosecond laser-assisted cataract surgery. A total of 33 eyelids received laser lateral canthotomy with the CO2 laser;only one eyelid had lateral canthotomy with cold-steel tenotomy scissors. Dockings were completed for all 34 eyes with eyelids receiving lateral canthotomies. The 33 eyes with eyelids that received laser canthotomy with the CO2 laser had successful femtosecond laser-assisted cataract surgery. The one eye with the eyelid that received cold-steel canthotomy could not have femtosecond laser-assisted cataract surgery despite successful docking because of pupillary constriction. The findings were statistically significant;Fisher Exact Test showed a p-value of 0.0294. Conclusion: Laser lateral canthotomy with CO2 laser is a safe and effective method to allow docking and completion of femtosecond laser-assisted cataract surgery.

From the mathematical model to the patient: The scientific and human aspects of artificial intelligence in gastrointestinal surgery

Recent medical literature shows that the application of artificial intelligence(AI)models in gastrointestinal pathology is an exponentially growing field,with pro-mising models that show very high performances.Regarding inflammatory bowel disease(IBD),recent reviews demonstrate promising diagnostic and prognostic AI models.However,studies are generally at high risk of bias(especially in AI models that are image-based).The creation of specific AI models that improve diagnostic performance and allow the establishment of a general prognostic fo-recast in IBD is of great interest,as it may allow the stratification of patients into subgroups and,in turn,allow the creation of different diagnostic and therapeutic protocols for these patients.Regarding surgical models,predictive models of post-operative complications have shown great potential in large-scale studies.In this work,the authors present the development of a predictive algorithm for early post-surgical complications in Crohn's disease based on a Random Forest model with exceptional predictive ability for complications within the cohort.The pre-sent work,based on logical and reasoned,clinical,and applicable aspects,lays a solid foundation for future prospective work to further develop post-surgical prognostic tools for IBD.The next step is to develop in a prospective and mul-ticenter way,a collaborative path to optimize this line of research and make it applicable to our patients.

Exploring the Role of Serum Cystatin C in Early Detection of Acute Kidney Injury among On-Pump Cardiac Surgery Patients: A Single-Center Investigation in Bangladesh

Background: Acute Kidney Injury (AKI) stands as a prominent postoperative complication in on-pump cardiac surgery, with repercussions on morbidity, mortality, and hospitalization duration. Current diagnostic criteria relying on serum creatinine levels exhibit a delayed identification of AKI, prompting an exploration of alternative biomarkers. Aims and Objectives: This study is designed to overcome diagnostic constraints and explore the viability of serum Cystatin C as an early predictor of Acute Kidney Injury (AKI) in individuals undergoing on-pump cardiac surgery. The investigation aims to establish the relationship between serum Cystatin C levels and the onset of AKI in patients subjected to on-pump cardiac surgery. Primary objectives involve the assessment of the diagnostic effectiveness of serum Cystatin C, its comparison with serum creatinine, and the exploration of its potential for the early identification and treatment of AKI. Methodology: Conducted as a single-center study at the cardiac surgery department of BSMMU in Bangladesh from September 2020 to August 2022, a comparative cross-sectional analysis involved 31 participants categorized into No AKI and AKI groups based on Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Data collection encompassed preoperative, post-CBP (cardiopulmonary bypass) conclusion at 2 hours, postoperative day 1, and postoperative day 2 intervals. Statistical analyses included Chi-squared tests, independent Student’s t-tests, and one-sample t-tests. Significance was set at P Results: The study revealed no significant differences in baseline characteristics between the No AKI and AKI groups, except for CPB time and cross-clamp time. Serum Cystatin C levels in the AKI group exhibited statistical significance at various time points, highlighting its potential as an early detector. Conversely, Serum Creatinine levels in the AKI group showed no statistical significance. The Receiver Operating Characteristic (ROC) curve analysis further supported the efficacy of serum Cystatin C, with an Area under the ROC Curve of 0.864 and a cut-off value of 0.55 (p Conclusion: This study supports the superior utility of serum Cystatin C as an early detector of AKI in on-pump cardiac surgery patients compared to serum creatinine. Its ability to identify AKI several hours earlier may contribute to reduced morbidity, mortality, and healthcare costs. The findings underscore the significance of exploring novel biomarkers for improved post-cardiac surgery renal function assessment.

New direction for surgery:Super minimally invasive surgery

The top goal of modern medicine is treating disease without destroying organ structures and making patients as healthy as they were before their sickness.Minimally invasive surgery(MIS)has dominated the surgical realm because of its lesser invasiveness.However,changes in anatomical structures of the body and reconstruction of internal organs or different organs are common after traditional surgery or MIS,decreasing the quality of life of patients post-operation.Thus,I propose a new treatment mode,super MIS(SMIS),which is defined as“curing a disease or lesion which used to be treated by MIS while preserving the integrity of the organs”.In this study,I describe the origin,definition,operative channels,advantages,and future perspectives of SMIS.

Perfusionist strategies for blood conservation in pediatric cardiac surgery

There is increasing concern about the safety of homologous blood transfusion during cardiac surgery,and a restrictive transfusion practice is associated with improved outcome.Transfusion-free pediatric cardiac surgery is unrealistic for the vast majority of procedures in neonates or small infants;however,considerable progress has been made by using techniques that decrease the need for homologous blood products or even allow bloodless surgery in older infants and children.These techniques involve a decrease in prime volume by downsizing the bypass circuit with the help of vacuumassisted venous drainage,microplegia,autologous blood predonation with or without infusion of recombinant(erythropoietin),cell salvaging,ultrafiltration and retrograde autologous priming.The three major techniques which are simple,safe,efficient,and cost-effective are:a prime volume as small as possible,cardioplegia with negligible hydric balance and circuit residual blood salvaged without any alteration.Furthermore,these three techniques can be used for all the patients,including emergencies and small babies.In every pediatric surgical unit,a strategy to decrease or avoid blood bank transfusion must be implemented.A strategy to minimize transfusion requirement requires a combined effort involving the entire surgical team with pre-,peri-,and postoperative planning and management.

Transurethral prostate surgery in prostate cancer patients: A population-based comparative analysis of complication and mortality rates

Objective:Prostate cancer(PCa)patients might experience lower urinary tract symptoms as those diagnosed with benign prostatic hyperplasia(BPH).Some of them might be treated for their lower urinary tract symptoms instead of PCa.We aimed to test the effect of PCa versus BPH on surgical outcomes after transurethral prostate surgery,namely complication and mortality rates.Methods:Within the American College of Surgeons National Surgical Quality Improvement Program database(2011-2016),we identified patients who underwent transurethral resection of the prostate,photoselective vaporization,or laser enucleation.Patients were stratified according to postoperative diagnosis(PCa vs.BPH).Univariable and multivariable logistic regression models evaluated the predictors of perioperative morbidity and mortality.A formal test of interaction between diagnosis and surgical technique used was performed.Results:Overall,34542 patients were included.Of all,2008(5.8%)had a diagnosis of PCa.The multivariable logistic regression model failed to show statistically significant higher rates of postoperative complications in PCa patients(odds ratio:0.9,95%confidence interval:0.7-1.1;p=0.252).Moreover,similar rates of perioperative mortality(p=0.255),major acute cardiovascular events(p=0.581),transfusions(p=0.933),and length of stay of more than or equal to 30 days(p=0.174)were found.Additionally,all tests failed to show an interaction between post-operative diagnosis and surgical technique used.Conclusion:Patients diagnosed with PCa do not experience higher perioperative morbidity or mortality after transurethral prostate surgery when compared to their BPH counterparts.Moreover,the diagnosis seems to not influence surgical technique outcomes.

Managerial perspectives of scaling up robotic-assisted surgery in healthcare systems:A systematic literature review

Objectives Robotic-assisted surgery(RAS)is a minimally invasive technique practiced in multiple specialties.Standard training is essential for the acquisition of RAS skills.The cost of RAS is considered to be high,which makes it a burden for institutes and unaffordable for patients.This systematic literature review(SLR)focused on the various RAS training methods applied in different surgical specialties,as well as the cost elements of RAS,and was to summarize the opportunities and challenges associated with scaling up RAS.Methods An SLR was carried out based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses reporting guidelines.The PubMed,EBSCO,and Scopus databases were searched for reports from January 2018 through January 2024.Full-text reviews and research articles in the English language from Asia-Pacific countries were included.Articles that outlined training and costs associated with RAS were chosen.Results The most common training system is the da Vinci system.The simulation technique,which includes dry-lab,wet-lab,and virtual reality training,was found to be a common and important practice.The cost of RAS encompasses the installation and maintenance costs of the robotic system,the operation theatre rent,personnel cost,surgical instrument and material cost,and other miscellaneous charges.The synthesis of SLR revealed the challenges and opportunities regarding RAS training and cost.Conclusions The results of this SLR will help stakeholders such as decision-makers,influencers,and end users of RAS to understand the significance of training and cost in scaling up RAS from a managerial perspective.For any healthcare innovation to reach a vast population,cost-effectiveness and standard training are crucial.

Preventive effect of probiotics on infections following colorectal cancer surgery:An umbrella meta-analysis

BACKGROUND Postoperative infections remain a significant source of morbidity among patients undergoing colorectal cancer(CRC)surgery.While probiotics have been pro-posed as a potential strategy to mitigate the risk of these infections,contemporary meta-analyses have produced conflicting findings.AIM To synthesize the available evidence regarding the prophylactic efficacy of probiotics in preventing infections following CRC surgery.METHODS A comprehensive search of PubMed and Scopus was conducted to identify relevant meta-analyses published up to February 2024.To assess the efficacy of probiotics on outcomes,relative risks(RR)and their corresponding 95%CI were pooled using a random effects model.RESULTS This comprehensive umbrella meta-analysis integrated eleven meta-analyses encompassing 11518 participants who fulfilled the inclusion criteria.Probiotics administration resulted in a statistically significant reduction in the incidence of total infections(RR:0.40,95%CI:0.31-0.51;moderate certainty),surgical site infections(RR:0.56,95%CI:0.49-0.63;high certainty),pneumonia(RR:0.38,95%CI:0.30-0.48;high certainty),urinary tract infections(RR:0.44,95%CI:0.31-0.61;moderate certainty),bacteremia(RR:0.41,95%CI:0.30-0.56;high certainty),and sepsis(RR:0.35,95%CI:0.25-0.44;high certainty).However,probiotics did not significantly affect intra-abdominal,central line,or peritoneal infections.CONCLUSION Probiotics have demonstrated potential in mitigating postoperative infectious complications among patients undergoing CRC surgery.

Application value of dexmedetomidine in anesthesia for elderly patients undergoing radical colon cancer surgery

BACKGROUND Colon cancer presents a substantial risk to the well-being of elderly people worldwide.With advancements in medical technology,surgical treatment has become the primary approach for managing colon cancer patients.However,due to age-related physiological changes,especially a decline in cognitive function,older patients are more susceptible to the effects of surgery and anesthesia,increasing the relative risk of postoperative cognitive dysfunction(POCD).There-fore,in the surgical treatment of elderly patients with colon cancer,it is of pa-ramount importance to select an appropriate anesthetic approach to reduce the occurrence of POCD,protect brain function,and improve surgical success rates.METHODS One hundred and seventeen patients with colon cancer who underwent elective surgery under general anesthesia were selected and divided into two groups:A and B.Group A received Dex before anesthesia induction,and B group received an equivalent amount of normal saline.Changes in the mini-mental state exami-nation,regional cerebral oxygen saturation(rSO2),bispectral index,glucose uptake rate(GluER),lactate production rate(LacPR),serum S100βand neuron-specific enolase(NSE),POCD,and adverse anesthesia reactions were compared between the two groups.RESULTS Surgical duration,duration of anesthesia,and intraoperative blood loss were comparable between the two groups(P>0.05).The overall dosage of anesthetic drugs used in group A,including propofol and remifentanil,was significantly lower than that used in group B(P<0.05).Group A exhibited higher rSO2 values at the time of endotracheal intubation,30 min after the start of surgery,and immediately after extubation,higher GluER values and lower LacPR values at the time of endotra-cheal intubation,30 min after the start of surgery,immediately after extubation,and 5 min after extubation(P<0.05).Group A exhibited lower levels of serum S100βand NSE 24 h postoperatively and a lower incidence of cognitive dysfunction on the 1st and 5th postoperative days(P<0.05).CONCLUSION The use of Dex in elderly patients undergoing radical colon cancer surgery helps maintain rSO2 Levels and reduce cerebral metabolic levels and the incidence of anesthesia-and surgery-induced cognitive dysfunction.

Comparative study on the efficacy of transoral robotic surgery and non-robotic surgery for tongue base tumors

Objective:To compare the efficacy of transoral robotic surgery(TORS)and non-robotic surgery(NRS)in the treatment of tongue base tumors.Methods:A total of 45 patients with tongue base tumors treated in our hospital were selected,and they were divided into the TORS group and NRS group according to different surgical methods.The surgical indicators and postoperative complications of patients in the two groups were compared and analyzed.Results:Compared with the NRS group,the operative time,bleeding volume and length of hospital stay were less in the TORS group,and the postoperative recurrence rate was less in the TORS group than that in the NRS group.The incidence rate of dysphagia and restricted mouth opening in the TORS group was lower than that in the NRS group within 30 d after surgery,and the difference was statistically significant(P<0.05).Conclusion:TORS has better minimally invasive advantages in the treatment of tongue base tumors,including less intraoperative bleeding,smaller trauma,shorter length of hospital stay and faster recovery.

Gold Standard for Skin Cancer Treatment: Surgery (Mohs) or Microscopic Molecular-Cellular Therapy (Curaderm)?

Non-melanoma skin cancers or keratinocyte cancers such as basal cell carcinoma and squamous cell carcinoma make up approximately 80% and 20% respectively, of skin cancers with the 6 million people that are treated annually in the United States. 1 in 5 Americans and 2 in 3 Australians develop skin cancer by the age of 70 years and in Australia it is the most expensive, amassing $1.5 billion, to treat cancers. Non-melanoma skin cancers are often self-detected and are usually removed by various means in doctors’ surgeries. Mohs micrographic surgery is acclaimed to be the gold standard for the treatment of skin cancer. However, a novel microscopic molecular-cellular non-invasive topical therapy described in this article, challenges the status of Mohs procedure for being the acclaimed gold standard.

Corneal re-innervation following refractive surgery treatments

Laser refractive surgery is one of the most performed surgical procedures in the world. Although regarded safe and efficient, it has side effects. All of the laser based refractive surgical procedures invoke corneal nerve injury to some degree. The impact of this denervation can range from mild discomfort to neurotrophic corneas. Currently, three techniques are widely used for laser vision correction: small incision lenticule extraction, laser-assisted keratomileusis in situ and photorefractive keratotomy. Each of these techniques affects corneal innervation differently and has a different pattern of nerve regeneration. The purpose of this review is to summarize the different underlying mechanisms for corneal nerve injury and compare the different patterns of corneal reinnervation.

Perioperative visual loss after spine surgery

Perioperative visual loss(POVL) is an uncommon, but devastating complication that remains primarily associated with spine and cardiac surgery. The incidence and mechanisms of visual loss after surgery remain difficult to determine. According to the American Society of Anesthesiologists Postoperative Visual Loss Registry, the most common causes of POVL in spine procedures are the two different forms of ischemic optic neuropathy: anterior ischemic optic neuropathy and posterior ischemic optic neuropathy, accounting for 89% of the cases. Retinal ischemia, cortical blindness, and posterior reversible encephalopathy are also observed, but in a small minority of cases. A recent multicenter case control study has identified risk factors associated with ischemic optic neuropathy for patients undergoing prone spinal fusion surgery. These include obesity, male sex, Wilson frame use, longer anesthetic duration, greater estimated blood loss, and decreased percent colloid administration. These risk factors are thought to contribute to the elevation of venous pressure and interstitial edema, resulting in damage to the optic nerve by compression of the vessels that feed the optic nerve, venous infarction or direct mechanical compression. This review will expand on these findings as well as the recently updated American Society of Anesthesiologists practice advisory on POVL. There are no effectivetreatment options for POVL and the diagnosis is often irreversible, so efforts must focus on prevention and risk factor modification. The role of crystalloids versus colloids and the use of α-2 agonists to decrease intraocular pressure during prone spine surgery will also be discussed as a potential preventative strategy.