王云鹏 陈光富 张旭 王保军 马鑫 史立新 李宏召 王春杨 艾青 杨国强
1中国人民解放军总医院泌尿外科 100853 北京
综 述
影响腹腔镜保留肾单位手术术后肾功能恢复的因素分析
王云鹏1陈光富1张旭1王保军1马鑫1史立新1李宏召1王春杨1艾青1杨国强1
1中国人民解放军总医院泌尿外科 100853 北京
微创肾部分切除术目前已广泛开展,较根治性肾切除有明显改善肾功能的优势。其技术难题是阻断肾血管后肾脏创面止血及重建,难免引起肾缺血损伤。学者们通过分析各种因素尽量改善患肾功能,但观点不一。这些因素主要有:年龄、合并症评分、身体质量指数、术前肾功能、肿瘤位置及大小、合并症、肾缺血时间及剩余肾体积比例等等。现简要总结目前报道的影响术后肾功能恢复因素,并期待有简单有效的肾功能保护技术,促进微创肾部分切除术的进一步发展和普及。
肾部分切除术;根治性肾切除;肾功能保护;机器人;腹腔镜
肾癌是泌尿系统常见的恶性肿瘤,全球每年约有27万新发病例,11.6万人死亡,其中90%为透明细胞癌。其恶性度高,远处转移率为20%~30%,约20%患者行肾切除手术治疗后出现复发或进展[1]。肾部分切除术(parcial nephrectomy, PN)可以得到和肾癌根治术(radical nephrectomy, RN)相同的肿瘤学效果,并能够保留肾单位,减少慢性肾病(chronic kidney disease, CKD)和心血管疾病发生率,生存时间长,生活质量高,已成为肾癌手术治疗的金标准[2]。随着腹腔镜肾部分切除术(laparoscopic parcial nephrectomy, LPN)的成熟和机器人辅助技术(robot assisted parcial nephrectomy, RAPN)的应用,相比于开放肾部分切除术 (open parcial nephrectomy, OPN)趋于微创化,出血少、减轻疼痛并缩短住院时间。最近,欧洲泌尿外科协会指南推荐T1期肾肿瘤由有丰富腹腔镜经验的外科医生行LPN[3]。如何提高手术技巧、保留足够的肾功能(renal function, RF)从而改善肾癌的预后,成为当今泌尿外科一大热点和难点。
对于RF的测定方法,血清肌酐(sCr)受年龄、性别、肌肉量和对侧正常肾代偿等影响,虽然常用于临床,但并不理想。而125I直接测定肾小球滤过率(glomerular filtration rate, GFR)是反映RF的金标准。MDRD (the modification of diet in renal disease)和CKD-EPI (the chronic kidney disease epidemiology collaboration)公式计算的eGFR (estimation of glomerular filtration rate)被认为是相对准确的GFR估计值[4]。研究发现有25%肾肿瘤患者,虽然sCr正常同时有正常的健侧肾,却伴有至少中度CKD(eGFR<60 ml·min-1·1.73 m-2),且eGFR下降约30%之前,sCr不会有明显升高[5, 6]。
目前认为,影响PN术后RF的因素主要有:术前因素,如年龄、性别、肿瘤大小及复杂性、术前“基础”RF、是否孤立肾等等;术中因素,如手术方式、缺血类型及时间、剩余肾组织体积等等[6]。其中术前“基础”RF主要由年龄、合并症、身体状态和既往有无肾脏手术史决定;剩余肾组织体积由肿瘤大小、位置及供血情况决定[7],外科医生可努力改善的是术中因素。
如何最大程度地减少肾脏缺血再灌注损伤是PN手术的关键点。缺血类型可分为肾脏热缺血和冷缺血。减少肾缺血损伤的手段主要包括缩短肾缺血时间和减小肾缺血范围。对于前者,传统观念认为肾脏热缺血时间(warm ischemia time, WIT)应<30 min,而更长时间的肾缺血RF是否明显下降 ,相关动物实验和小样本、回顾性临床试验研究发现即使肾缺血时间>30 min,术后RF也可以恢复[8]。临床主动脉瘤修补术中肾脏WIT≥30 min,术后60%患者无明显肾损伤,55%患者可在一段时间后恢复原有RF水平[9]。Parekh等[10]一项关于肾脏耐受缺血时间的临床研究,发现40例患者中的82.5%肾缺血时间>30 min,甚至达到61 min, 术后早期未出现急性肾损伤(acute kidney injury, AKI)或仅轻微RF改变。但是许多研究发现,长时间的肾缺血RF会明显下降。
1.1 肾脏缺血时间可以很长
Lane等[11]对2 402例连续的T1期肾肿瘤行PN和RN的对比研究,发现术后中重度CKD(eGFR<45 ml·min-1·1.73 m-2)的发生率,在PN中肾脏WIT<30 min时为11%,肾脏WIT>30 min时为19%,而RN术后中重度CKD的发生率可达35% 。Porpiglia等用99mTc-MAG-3核素肾扫描分析18例WIT>30 min的LPN患者,发现虽然术后3个月总体RF无明显下降(eGFR:91.6vs.79.1 ml·min-1·1.73 m-2;P≥0.05),但患侧RF由术前48.3%, 降至术后第5天36.9%,术后3个月40.6%,术后1年只恢复到42.8%。术后RF恢复由术中切除肾组织的最大厚度和WIT决定,WIT>30 min时患侧RF只能部分恢复,而更长时间的热缺血尤其是WIT>32 min则会出现RF的永久性丧失[12]。
1.2 术后肾功能变化有时间节段性
Porpiglia等[13]发现双肾患者PN术后RF短期下降,在术后3周~3个月可恢复至一个新的较高的水平 。其对54例双肾患者LPN术后患侧RF进行了4年的长期观察,发现术后3个月患侧RF明显下降,下降时间越长,GFR恢复程度越差。随后,患肾RF在术后3个月~4年维持一个稳定期。 Porpiglia等[14]还发现患者年龄和WIT是术后3个月患侧肾功能变化的独立预测因素,长期的预测因素只有WIT。
1.3 肾缺血时间短能保护肾功能
肾缺血时间缩短对RF的影响 ,多数学者认为[6, 13, 15~17],WIT在20~25 min时肾脏损伤是暂时和可逆的,PN术后近、远期RF无明显改变。一些研究证明[13, 16, 18]WIT在25~30 min,术后RF明显恶化,说明WIT是其预测因素之一。近期Becker等[17]学者建议肾脏WIT应控制在20 min内。更有报道[15]每增加一分钟的肾缺血,就会增加5%~6%发生AKI的概率,进而导致严重的CKD,这对LPN或RAPN具有较高的技术挑战。随着技术逐渐成熟和新方法的应用,如“早松钳”(early unclamping)技术[19]及“滑夹”(sliding-clip)等技术[20]均明显缩短WIT,LPN的WIT由31 min降至14 min,WIT的缩短与术后RF改善明显相关,eGFR下降幅度由20.3%改善至10.6%[20]。Gill等的“零缺血”(zero ischemia)技术是高选择分离肾动静脉分支结合控制性降压,使WIT降至0,术后6个月放射性核素测定患肾GFR下降10%,平均切除肾组织体积18%[21]。Thompson等[22]选择解剖不复杂、外科容易处理的体积小、位置浅表或外生型肾肿瘤,应用挤压瘤旁肾组织而不阻断肾动脉的“无缺血”(No ischemia)技术对孤立肾患者行OPN和LPN术后近、远期RF进行研究,发现WIT平均21 min的热缺血组(n=362)比无缺血组(n=96)发生AKI和新发CKD的概率明显升高。另一项对双肾患者行OPN术的类似研究,发现肾动脉阻断组(n=164)与不阻断组(n=64)CKD的发生率分别为24.4%和12.5%[23]。Kaczmarek等[24]对多中心886例RAPN的研究发现,肾动脉不阻断组(n=66)虽然出血较多,但手术时间明显缩短,术后eGFR下降幅度较肾动脉阻断组小(2%vs.6%,P=0.008)。可以肯定的是,缩短肾缺血时间可明显改善LPN术后的RF。
如何减小肾缺血范围,与传统的肾动脉主干阻断技术相比,分支动脉阻断的技术被提出[25],根据术前影像学血管成像分析,高选择性阻断肿瘤区供血的分支动脉,肿瘤的切除以及创面的缝合都在局部肾实质缺血的情形下完成。 “健康”的剩余肾组织保持正常的血供,对于RF的保护和术后恢复,有显著的优势。术后RF结果与阻断肾动脉分支数量明显相关,阻断的分支越少,肾功能恢复越好。Simone等[26]应用术前高选择栓塞肾肿瘤滋养动脉,随后行不阻断肾血管的LPN,观察到患侧RF在术后3个月下降9%,术后1年下降5%。Desai等[27]将121例RAPN分为高选择阻断肾动脉分支组和肾动脉主干阻断组,虽然前者瘤体偏大且更复杂,但术后剩余肾体积比肾动脉主干阻断组略多(95%vs.90%,P=0.07),出院时eGFR下降明显较少(0%vs.11%,P=0.01),随访4~6个月最终eGFR下降较少(11%vs.17%,P=0.03)。虽然精确的靶分支肾动脉的确定可凭术前DSCTA(dual source computed tomograghy angiography, DSCTA)以及术中肉眼观察肾组织缺血变白来判断,但因主观性过强,缺乏客观的依据,可能会造成血管漏扎或多扎等情形,尤其是后者,会损失正常的剩余肾组织。于是Gill[28]提出判断剩余肾组织动脉灌注的客观方法,即腹腔镜实时多普勒超声记录波形和静注ICG(indigo cyanine green)辅以机器人红外线成像。故此,分支肾动脉阻断的技术仍有争议。
低温保护是常用的预防肾缺血再灌注损伤方法,优点是变热缺血为冷缺血,使肾脏代谢降低,许多酶系统的活性也降低,减少ATP的消耗,有效保护RF,明显延长手术时限,尤其适用于复杂肾肿瘤和不熟练的术者。研究证实冷缺血时间(cold ischemia time, CIT)比WIT手术时限延长,对肾脏保护作用明显[29]。Lane等[7]的一项多中心研究,对660例孤立肾PN手术的回顾研究,其中300例冷缺血和360例热缺血患者术后3个月平均eGFR分别下降21%和22%(P=0.7),而术中冷缺血时间和热缺血时间平均为45 min和22 min(P<0.001)。且肾脏可以耐受更长时间的冷缺血,肾移植手术中,尸肾可低温保存20 h,移植成功后eGFR能恢复至45~50 ml·min-1·1.73 m-2。研究发现肾脏适宜的保护温度是15°,而肾脏降温至20~25°即可达到耐受3 h缺血的效果[30]。Iida等[31]发现CIT<44 min可显著预防肾功能下降,eGFR恢复至45 ml·min-1·1.73 m-2。但Becker等[17]认为即使是冷缺血也不应超过2 h,最好是在35 min内。Yossepowitch等[32]对592例OPN患者资料进行多因素分析,证实CIT<35 min较为安全,可导致术后早期eGFR下降,术后12个月未见eGFR明显改变。在传统的开放性手术中最常用的方法是肾周加冰屑降温[33],夹闭肾动脉后表面冰屑降温,10 min后开始切除肿瘤。虽然肾脏周围加冰屑的方法在LPN[34]和RAPN[35]中也有应用,但是主要缺点是:冷却的不均质性;反复进行冰屑添加,延长了手术时间;降温后影响手术视野;有局部肾皮质坏死的可能。而腹腔镜下肾部分切除术降温方式有:动脉插管灌注[36]、经输尿管逆行灌注冰水降温方法[37]、肾脏表面冰袋降温等等。其中经肾动脉插管灌注降温法效果确切,但灌注前需要进行肾动脉血管造影,需要相关科室合作,且对肾脏血管损伤大,操作风险性高。而经输尿管逆行灌注冰水的方法,利用肾脏原有的管道系统,通过向集合系统内灌注冰水,无须特殊的器械,简单易行,可使肾髓质温度降至21°,肾皮质温度降至24°。缺点是灌注量和压力不易控制,压力过高可会造成肾单位的破坏,而早期肾皮质肿瘤降温效果欠佳。Crain等[38]应用F12双腔套管为灌注引流管道,改善了灌注情况。显然,低温技术对RF的保护作用是肯定的。
近期有学者认为,剩余肾体积比传统认为的WIT更能预测PN术后近、远期RF结果[39, 40]。Simmons等[41]提出减少肾缺血时间和低温技术对RF保护作用不大,尤其是对远期RF的影响,WIT和肾实质保留体积(percent functional volume preservation, PFVP)可能与近期最低GFR相关,术前Charlson伴随症状评分和PFVP才与最终GFR相关。认为最重要的是精细的肿瘤切除和肾脏重建,包括:高分辨率的术前肾肿瘤影像定位;精准的活体成像引导下切除肿瘤;避免阻断邻近的动脉分支;重建时避免缝合过度正常肾组织等。
孤立肾研究可以消除健肾对术后RF的代偿影响,虽然有研究表明孤立肾比双肾更加耐受缺血[42]。Lane等[7]对660例孤立肾的多中心研究,分支结扎肾动脉肾部分切除术,发现术后RF结果取决于术前“基础”RF和术后剩余肾组织体积,即肾的“质”和“量”,而不是WIT。为证实其结论,Thompson等[43]一项关于孤立肾肾部分切除术的多因素分析,证明术前“基础”RF(P<0.001)、术后剩余肾组织体积(P=0.009)和WIT(P=0.021)与术后短期RF下降、导致AKI和是否需要透析明显相关;“基础” RF (P<0.0001)、术后剩余肾组织体积(P<0.001)和WIT是否超过25 min(hazard ratio:2.27;P=0.049)与远期RF恢复和新发Ⅳ期CKD (eGFR15~30 ml·min-1·1.73 m-2)相关。说明术前RF比术后剩余肾体积预测术后RF作用更强,可能与剩余肾单位加倍滤过,以代偿损伤的肾单位有关。
究竟哪个因素对术后RF影响最大 ,Gill[28]认为几种影响因素互为因果。WIT仍是重要的指标,尤其对于孤立肾。其与肿瘤复杂性和切除肾体积明显相关。肾肿瘤越复杂,切除肾体积越大,同时WIT越长。肾的“质”取决于患者自身和肿瘤因素,外科医生可以努力改善的是WIT和保留肾的“量”。理想的PN是:完整切除肿瘤,精细保留瘤旁少量肾组织,保证切缘阴性和创面安全,尽量减少剩余肾的缺血,减少并发症,迅速恢复RF。并提出首先考虑肾动脉,其次才是肿瘤的解剖学概念。肾血管解剖清晰可运用更精准的手术技巧。优势是仅保留1~2 mm的瘤旁肾组织,可以最大限度保留剩余正常肾组织,尽量减少肾缺血引起的AKI和CKD。
总之,随着机器人和高新影像技术的引入,肾肿瘤位置及供血动脉术前准确定位分析,术中高选择阻断分支肾动脉,肿瘤得到精准切除,尽可能保留正常肾组织,保证切缘阴性,开发术后能够计算剩余肾体积的影像学技术,寻求更客观的肾功能扫描和生物学指标,及时准确判断肾功能下降情况,可以更好的预防肾损伤,降低心血管事件及死亡率,提高患者生存率及生活质量。
[1]Ljungberg B, Campbell SC, Choi HY, et al. The epidemiology of renal cell carcinoma. Eur Urol, 2011, 60(4):615-621.
[2]Tan HJ, Norton EC, Ye Z, et al. Long-term survival following partial vs radical nephrectomy among older patients with early-stage kidney cancer. JAMA, 2012, 307(15):1629-1635.
[3]Ljungberg B, Bensalah K, Canfield S, et al. EAU guidelines on renal cell carcinoma: 2014 update. Eur Urol, 2015,67(5):913-924.
[4]Michels W M, Grootendorst D C, Verduijn M, et al. Performance of the Cockcroft-Gault, MDRD, and new CKD-EPI formulas in relation to GFR, age, and body size. Clin J Am Soc Nephrol, 2010, 5(6):1003-1009.
[5]Huang W C, Levey A S, Serio A M, et al. Chronic kidney disease after nephrectomy in patients with renal cortical tumours: a retrospective cohort study. Lancet Oncol, 2006, 7(9):735-740.
[6]Lane B R, Babineau D C, Poggio E D, et al. Factors predicting renal functional outcome after partial nephrectomy. J Urol, 2008, 180(6):2363-2369.
[7]Lane B R, Russo P, Uzzo R G, et al. Comparison of cold and warm ischemia during partial nephrectomy in 660 solitary kidneys reveals predominant role of nonmodifiable factors in determining ultimate renal function. J Urol, 2011, 185(2):421-427.
[8]Godoy G, Ramanathan V, Kanofsky J A, et al. Effect of Warm Ischemia Time During Laparoscopic Partial Nephrectomy on Early Postoperative Glomerular Filtration Rate. J Urol, 2009, 181(6):2438-2445.
[9]Jean-Claude J M, Reilly L M, Stoney R J, et al. Pararenal aortic aneurysms: the future of open aortic aneurysm repair. J Vasc Surg, 1999, 29(5):902-912.
[10]Parekh D J, Weinberg J M, Ercole B, et al. Tolerance of the human kidney to isolated controlled ischemia. J Am Soc Nephrol, 2013, 24(3):506-517.
[11]Lane B R, Fergany A F, Weight C J, et al. Renal functional outcomes after partial nephrectomy with extended ischemic intervals are better than after radical nephrectomy. J Urol, 2010, 184(4):1286-1290.
[12]Porpiglia F, Renard J, Billia M, et al. Is renal warm ischemia over 30 minutes during laparoscopic partial nephrectomy possible? One-year results of a prospective study. Eur Urol, 2007, 52(4):1170-1178.
[13]Porpiglia F, Fiori C, Bertolo R, et al. The effects of warm ischaemia time on renal function after laparoscopic partial nephrectomy in patients with normal contralateral kidney. World J Urol, 2012, 30(2):257-263.
[14]Porpiglia F, Fiori C, Bertolo R, et al. Long-term functional evaluation of the treated kidney in a prospective series of patients who underwent laparoscopic partial nephrectomy for small renal tumors. Eur Urol, 2012, 62(1):130-135.
[15]Thompson RH, Lane BR, Lohse CM, et al. Every minute counts when the renal hilum is clamped during partial nephrectomy. Eur Urol, 2010, 58(3):340-345.
[16]Funahashi Y, Hattori R, Yamamoto T, et al. Ischemic renal damage after nephron-sparing surgery in patients with normal contralateral kidney. Eur Urol, 2009, 55(1):209-215.
[17]Becker F, Van Poppel H, Hakenberg OW, et al. Assessing the impact of ischaemia time during partial nephrectomy. Eur Urol, 2009, 56(4):625-634.
[18]Pouliot F, Pantuck A, Imbeault A, et al. Multivariate analysis of the factors involved in loss of renal differential function after laparoscopic partial nephrectomy: a role for warm ischemia time. Can Urol Assoc J, 2011, 5(2):89-95.
[19]Nguyen MM, Gill IS. Halving ischemia time during laparoscopic partial nephrectomy. J Urol, 2008, 179(2):627-632.
[20]Benway BM, Wang AJ, Cabello JM, et al. Robotic partial nephrectomy with sliding-clip renorrhaphy: technique and outcomes. Eur Urol, 2009, 55(3):592-599.
[21]Gill IS, Patil MB, Abreu AL, et al. Zero ischemia anatomical partial nephrectomy: a novel approach. J Urol, 2012, 187(3):807-814.
[22]Thompson RH, Lane BR, Lohse CM, et al. Comparison of warm ischemia versus no ischemia during partial nephrectomy on a solitary kidney. Eur Urol, 2010, 58(3):331-336.
[23]Kopp RP, Mehrazin R, Palazzi K, et al. Factors affecting renal function after open partial nephrectomy-a comparison of clampless and clamped warm ischemic technique. Urology, 2012, 80(4):865-870.
[24]Kaczmarek BF, Tanagho YS, Hillyer SP, et al. Off-clamp robot-assisted partial nephrectomy preserves renal function: a multi-institutional propensity score analysis. Eur Urol, 2013, 64(6):988-993.
[25]Shao P, Qin C, Yin C, et al. Laparoscopic partial nephrectomy with segmental renal artery clamping: technique and clinical outcomes. Eur Urol, 2011, 59(5):849-855.
[26]Simone G, Papalia R, Guaglianone S, et al. Zero ischemia laparoscopic partial nephrectomy after superselective transarterial tumor embolization for tumors with moderate nephrometry score: long-term results of a single-center experience. J Endourol, 2011, 25(9):1443-1446.
[27]Desai MM, de Castro Abreu AL, Leslie S, et al. Robotic Partial Nephrectomy with Superselective Versus Main Artery Clamping: A Retrospective Comparison. Eur Urol, 2014, 66(4):713-719.
[28]Gill IS. Towards the ideal partial nephrectomy. Eur Urol, 2012, 62(6):1009-1012.
[29]Ward JP. Determination of the Optimum temperature for regional renal hypothermia during temporary renal ischaemia. Br J Urol, 1975, 47(1):17-24.
[30]Wakabayashi Y, Narita M, Kim CJ, et al. Renal hypothermia using ice slush for retroperitoneal laparoscopic partial nephrectomy. Urology, 2004, 63(4):773-775.
[31]Iida S, Kondo T, Amano H, et al. Minimal effect of cold ischemia time on progression to late-stage chronic kidney disease observed long term after partial nephrectomy. Urology, 2008, 72(5):1083-1089.
[32]Yossepowitch O, Eggener SE, Serio A, et al. Temporary renal ischemia during nephron sparing surgery is associated with short-term but not long-term impairment in renal function. J Urol, 2006, 176(4 Pt 1):1339-1343, 1343.
[33]Uzzo RG, Novick AC. Nephron sparing surgery for renal tumors: indications, techniques and outcomes. J Urol, 2001, 166(1):6-18.
[34]Porpiglia F, Volpe A, Billia M, et al. Laparoscopic versus open partial nephrectomy: analysis of the current literature. Eur Urol, 2008, 53(4):732-743.
[35]Rogers CG, Ghani KR, Kumar RK, et al. Robotic partial nephrectomy with cold ischemia and on-clamp tumor extraction: recapitulating the open approach. Eur Urol, 2013, 63(3):573-578.
[36]Janetschek G, Abdelmaksoud A, Bagheri F, et al. Laparoscopic partial nephrectomy in cold ischemia: renal artery perfusion. J Urol, 2004, 171(1):68-71.
[37]Landman J, Venkatesh R, Lee D, et al. Renal hypothermia achieved by retrograde endoscopic cold saline perfusion: technique and initial clinical application. Urology, 2003, 61(5):1023-1025.
[38]Crain DS, Spencer CR, Favata MA, et al. Transureteral saline perfusion to obtain renal hypothermia: potential application in laparoscopic partial nephrectomy. JSLS, 2004, 8(3):217-222.
[39]Mir MC, Campbell RA, Sharma N, et al. Parenchymal volume preservation and ischemia during partial nephrectomy: functional and volumetric analysis. Urology, 2013, 82(2):263-268.
[40]Simmons MN, Fergany AF, Campbell SC. Effect of parenchymal volume preservation on kidney function after partial nephrectomy. J Urol, 2011, 186(2):405-410.
[41]Simmons MN, Hillyer SP, Lee BH, et al. Functional recovery after partial nephrectomy: effects of volume loss and ischemic injury. J Urol, 2012, 187(5):1667-1673.
[42]Askari A, Novick AC, Stewart BH, et al. Surgical treatment of renovascular disease in the solitary kidney: results in 43 cases. J Urol, 1982, 127(1):20-22.
[43]Thompson RH, Lane BR, Lohse CM, et al. Renal function after partial nephrectomy: effect of warm ischemia relative to quantity and quality of preserved kidney. Urology, 2012, 79(2):356-360.
Protection of renal function after laparoscopic partial nephrectomy
WangYunpeng1ChenGuangfu1ZhangXu1WangBaojun1MaXin1ShiLixin1LiHongzhao1WangChunyang1AiQing1YangGuoqiang1
(1Department of Urology, Chinese PLA General Hospital, Beijing 100853, China)
Zhang Xu, xzhang@foxmail.com
Minimal invasive surgery is widely performed, and partial nephrectomy has the advantage of more significantly improving renal function than radical nephrectomy. The technique problem is the hemostasis and reconstruction of the kidney after blocking renal blood vessels, which causes renal ischemia injury. Scholars have analyzed various factors to improve the renal function, but the opinions are controversial. These factors mainly include age, Charlson score(CS), body mass index (BMI), preoperative renal function, tumor size, location, complications, renal ischemia time and percent functional volume preservation, etc. This review briefly summarizes the factors influencing the postoperative recovery of renal function currently reported. It is expected to have a simple and effective protective measure for renal function, which can promote the further development of minimally invasive partial nephrectomy and popularization.
partial nephrectomy; radical nephrectomy; renal function protection; robot; laparoscope
张旭,xzhang@foxmail.com
2015-08-26
R737.11
A
2095-5146(2015)06-380-05