| Background: Renal angiomyolipoma(RAML),also known as renal hamartoma,is a common benign tumor of the kidney.It mainly contains mature or immature fat tissue,smooth muscle tissue and thick-walled blood vessels.It is commonly divided into two types which are tuberous sclerosis complex(TSC)related RAML and sporadic RAML.Sporadic RAMLs are usually detected during body examination since few symptom is obvious at early stage.However,some patients may suffer from low back pain,abdominal pain,hematuria,and soreness in the waist due to the increase in tumor size and they may accept medical intervention for these unwellness.Being different with the simple RAML,patients with TSC related RAML usually have a clear family history and they always have angiomyolipomas of both kidneys.They may also suffer from cheek lipoid adenoma,brain retardation or epilepsy.Comparing with sporadic RAML which has smaller tumor size and slower growing speed,TSC-RAML often occurs in early ages and the condition of disease is much more complicated.The diagnosis of RAML depends on imaging examination and common imaging examination methods such as CT,ultrasonography and MR all have good diagnostic value for the diagnosis of RAML.Though the diagnosis of RAML is not a difficult procedure,the treatment of RAML is complicated.Since RAML is benign renal mass which does not need confine operation,the general principle of RAML's treatment is saving healthy renal unit as much as possible as well as avoiding sudden rupture and bleeding.Currently,urologist widely accept the follow-up criteria bounded by 4 cm in tumor diameter while some other scholars believe that all patients with symptoms should accept medical treatment regardless of the tumor size.Besides,RAML is highly heterogeneous which demands doctors to carry out individualized treatment panels for each patient based on their condition.Actually,when RAML patients who have suffered from symptoms come for medical treatment,the diameter of tumor would have possibly larger than 4 cm.Some patients' tumor is so big that it can even be touched from body surface.Besides,there are emergency situations that some patients' tumor spontaneously ruptured and caused serious internal bleeding which may requires emergency surgery,so that it is quite common for urology doctors to deal with complicated RAML in their daily work and it would benefit patients if doctors can evaluate surgical difficulty before surgery to design the best treatment method for patients.However,there are not any existing reliable methods to predict the nephron sparing surgery difficulty for RAML by now.R.E.N.A.L nephrometry score system is commonly used in clinical practice which consists Radius(tumor size in maximal diameter),Exophytic/endophytic properties of the tumor,Nearness of tumor deepest portion to the collecting system or sinus,Anterior /posterior descriptor and the Location relative to the polar line.This score system is designed for renal malignancies(especially renal clear cell caicinoma).Due to the difference between RAML and RCC,the R.E.N.A.L nephrometry score may not properly evaluate the surgical difficulty for RAML's nephron sparing surgery.Therefore,this study hopes to explore and validate the modified scoring system for RAML's nephron sparing surgery,and compare it with the R.E.N.A.L nephrometry score system to validate the modified scoring system.Objective: Establish modified scoring system which based on R.E.N.A.L nephrometry score system and verify the estimated clinic value of the modified scoring system for the difficulty of nephron sparing surgery of RAML.Methods: Retrospective analysis of 162 patients with renal angiomyolipoma who undergoing nephron sparing surgery in our hospital,evaluate the patient's surgical difficulty according to the patient's operation time,blood loss volume and other indicators to divide all patients into low difficulty group,medium difficulty group and high difficulty group.The sensitivity and specificity of R.E.N.A.L nephrometry score and modified scoring system are verified respectively.Investigate the difference in surgical time,intraoperative blood loss,surgical methods,postoperative hospital stay time,postoperative complications,and the relationship between the scores of the different score groups in the modified scoring system.Results: A total of 162 patients were enrolled in this study.All patients were divided into three groups according to their actual surgical difficulty.Group A contains 75 patients,group B contains 52 patients and group C contains 35 patients.There were no significant differences in age,gender,and tumor location between the three groups while the difference between tumor size,tumor distance from the sinus and the richness of tumor blood supply was statistically significant.All patients were divided into low score group,medium score group and high score group according to the modified scoring system and these three groups included 71,68,and 23 patients respectively.As for operation time,the difference between the low difficulty group and the high difficulty group,the difference between the medium difficulty group and the high difficulty group were statistically significant.As for bleeding volume,the differences between all three groups were statistically significant.There was no statistically difference between these groups on the postoperative hospital stay time.As for surgical methods,60 patients underwent laparoscopic nephron sparing surgery and 11 patients underwent open surgery in low score group.In media score group,44 patients underwent laparoscopic nephron sparing surgery and 24 patients underwent open surgery.In high score group,7 patients underwent laparoscopic nephron sparing surgery,16 patients underwent open surgery,and the differences between all the three groups were statistically significant.The surgical procedures changing rate in all three groups were 4.2%,17.6%,and 39.1% respectively.The comparison between each group indicated the high score group have statistically difference between the other two groups.The difference between the medium score group and the high score group was statistically significant.In comparison with the R.E.N.A.L.Nephrometry Score,the sensitivities of the modified scoring system to each surgical difficulty were 71.1%,59.2%,54.1%,and the specificities were 80.2%,65.5%,and 97.6%,while the R.E.N.A.L.Nephrometry Score's sensitivities were 51.3%,42.9%,35.1%,and the specificities were 68.6%,50.4%,and 95.2% respectively.Except for the specificities of high difficulty surgery,the differences of other groups were statistically obvious.Conclusion: 1.Modified scoring system has good clinic value for evaluating the difficulty of RAML's nephron sparing surgery,surgery with higher scores is more difficult to perform.2.Compared with the traditional R.E.N.A.L.Nephrometry Score,the improved scoring system has certain advantages in sensitivity,specificity of surgical difficulty assessment.The modified scoring system is more suitable for evaluating the difficulty of RAML's nephron sparing surgery. |
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