Clinical observation of endoscopic skull base reconstruction with an anterolateral thigh free fascia flap

Objective:Radiation osteonecrosis of the skull base after radiotherapy for nasopharyngeal carcinoma is one of the most serious complications,affecting patient survival and quality of life.To date,surgical resection is the main treatment for radiation osteonecrosis.The repair after the operation is very important.Inappropriate repair or lack of repair can easily cause local infection that can even spread to the brain,aggravating osteonecrosis.This study aimed to verify the feasibility and safety of the ante-rolateral thigh free fascia flap in repairing large skull base defects.Methods:From June 2021 to July 2022,a total of 12 patients with a history of radiotherapy for naso-pharyngeal carcinoma received surgical treatment at the Department of Otolaryngology Head&Neck Surgery,Sir Run Run Shaw Hospital,Zhejiang University School of Medicine.All patients were diagnosed with radiation osteonecrosis of the skull base with large skull base defects.During the endoscopic operation,a free anterolateral thigh fascia flap was used to repair the skull base and complete vascular anastomosis reconstruction.The preoperative and postoperative pain scores were retrospectively analyzed,and the dynamic changes in endoscopic surgery sites were observed.Results:The 12 patients had a median age of 58 y,with 8(66.7%)males and 4(33.3%)females.The median headache score for the patients was 5(4-7)before surgery.The patient's headache was significantly relieved postoperatively,with 11 patients having a score of 0 and one patient having a score of 1.The stench was completely resolved after the operation.There were no serious complications during the perioperative period or 12 months after the operation.Conclusion:The application of anterolateral thigh free fascia flap in skull base reconstruction is a safe and reliable reconstruction technique suitable for endoscopic surgical repair of large-scale skull base necrosis.

The application of anterolateral thigh flap in post-operative repairing of vulva tumor

Objective： The aim of this study was to evaluate the value of the application of anterolateral thigh flap in postoperative repairing of vulva tumor. Methods： Anterolateral thigh flap with the descending branch of the lateral circumflex femoral artery and the pedicle of anterolaterat thigh cutaneous nerve was used in primary repairing of the defect from postoperative vulva tumor, the sizes of the flaps ranged from 10 cm ×14 cm-14 cm× 20 cm. Results： All flaps survived, during a follow-up of 2 to 12 months, the appearance of the flaps was satisfactory with sensitive function without local recurrences. Conclusion： Anterelateral thigh flap has fairly long vessel pedicle, wider vessel diameter, and is in the covert area. Anterolateral thigh flap with sensory nerve is the ideal choice for postoperative repairing of vulva tumor.

The application of thin flap repairing method after reascularization in femoral anterolateral free flap

Objective: To summarize the application and effect of thin flap repairing method after reascularization in femoral anterolateral free flap. Methods: From May 2013 to October 2015, 20 cases of patients received femoral anterolateral free flap transplantation, with the flap transported to the recipient site. After reascularization, the phase I of thin flap repairing was performed in each 'vein type'area. Among those, there existed 8 cases of direct suture in the donor site, and 12 cases of skin transplantation by intermediate split thickness skin graft. Results: All the postoperative flaps survived, with 2 cases of vascular crisis and 2 cases of poor venous return at the edge of flap. No complications such as flap infection and necrosis occurred. Wounds and incisions in donor and recipient sites were healed in phase I. 20 cases of patients had been followed up for 5-24 months, and the average follow-up time was 15 months. The skin texture of flap was similar to the surrounding skin, with good abrasion resistance, no ulceration and no phase II flap repairing;the sensation of flap recovered to S3-S4 level;the two-point discrimination was 3.5-6.0 mm, with the average value of 5.0 mm. The function of patients' fingers recovered well without any complications such as contracture and deformity etc. In the last follow-up, Testative Evaluation Standard of Upper Limb Function, which was established by Chinese Medical Society for Surgery of Hand, was used to assess efficacy, and the evaluation results were as follows: excellent in 9 cases, good in 5 cases, fair in 6 cases;in accordance with the evaluation criteria listed in Michigan Hand Outcome Questionnaire (used to assess patients' satisfaction with the appearance of flaps after operation, and the results were as follows: very satisfactory in 9 cases, satisfactory in 9 cases, and moderate in 2 cases. Conclusions: After reascularization in femoral anterolateral free flap grafting, phase I of thin repairing has small effects on flap vascularization, with a satisfactory appearance of the flap.

Free Flow-through Anterolateral Thigh Flaps for Wrist High-tension Electrical Burns:A Retrospective Case Series

Objective The objective of this report was to demonstrate the clinical application of free flow-through anterolateral thigh flaps for the treatment of high-tension electrical wrist burns.Methods We collected the data of 8 patients with high-tension electrical wrist burns admitted to Beijing Jishuitan Hospital from January 2014 to December 2018.The clinical and pathological data were extracted from electronic hospital medical records.We obtained follow-up information through clinic visits.Results The injury sites for all 8 patients were the wrists,specifically 5 right and 3 left wrists,all of which were on the flexor side.Five patients had ulnar artery embolism necrosis and patency,with injury to the radial artery.Two patients had ulnar and radial arterial embolization and necrosis.The last patient had ulnar arterial embolization and necrosis with a normal radial artery.After debridement,the wound area ranged from 12 cm×9 cm to 25 cm×16 cm.The diagnoses for the eight patients were type II to type III high-tension electrical wrist burns.Free flow-through anterolateral thigh flaps(combined with great saphenous vein transplantation if necessary)were used to repair the wounds.The prognosis for all patients was good after six months to one year of follow-up.Conclusion Treating wrist types II and III high-tension electrical burns is still challenging in clinical practice.The use of free flow-through anterolateral thigh flaps(combined with great saphenous vein transplantation if necessary)to repair the wound and to restore the blood supply for the hand at the same time is a good choice for treating severe wrist electrical burns.

Successful reconstruction of an ankle defect with free tissue transfer in a hemophilia A patient with repetitive hemoarthrosis:A case report

BACKGROUND Hemophilia, an uncommon yet consequential hereditary bleeding disorder, manifests as two clinically indistinguishable forms that hinder the normal functioning of the coagulation cascade. This impairment renders individuals more susceptible to excessive bleeding during significant surgical interventions. Moreover, individuals with severe hemophilia frequently encounter recurring hemarthrosis, resulting in progressive joint destruction and, subsequently, the need for hip and knee replacement surgeries.CASE SUMMARY The patient was a 53-year-old man with hemophilia A as the underlying disease and had self-injected factor Ⅷ twice weekly for several decades. He had undergone ankle fusion surgery for recurrent hemarthrosis at the Department of Orthopedic Surgery 1 mo prior and was referred to our department because of skin necrosis after a hematoma at the surgical site. An anterolateral thigh perforator free flap was created after three cycles of factor Ⅷ administration in addition to the concomitant administration of tranexamic acid(TXA)(Transamin 250 mg cap, 1 cap tid, q8h). After the operation, from postoperative days(PODs) 1-5, the factor Ⅷ dose and interval were maintained, and q12h administration was tapered to q24h administration after POD 6. Because the patient’s flap was stable 12 d after the operation, factor Ⅷ administration was tapered to twice a week. At 6 mo follow-up, the patient recovered well without any complications.CONCLUSION To the best of our knowledge, there are very few reports of successful free flaps in patients with hemophilia, and none have been reported in patients with hemophilia A. Moreover, there are several reports on the efficacy of TXA in free flaps in general patients;however, there are no case reports of combining factor Ⅷ and TXA in patients with hemophilia. Therefore, we report this case to contribute to future academic research.

Unusual case of a free anterolateral thigh flap partial necrosis in a COVID-19 positive young male following extremity reconstruction

Free flap procedure provides an overall success rate of 97%, which decreases to 85% in hypercoagulable states. COVID-19, as a pro-thrombotic disorder, therefore seems detrimental to free flap survival. We encountered a case of unique pattern of free flap partial failure in a young male who underwent extremity reconstruction. The patient was diagnosed as COVID-19 positive on the 3rd day post-reconstruction. The flap survived well for the first 7 days post-operatively, but gradually the skin got necrosed and the subcutaneous fat layer was preserved when debriding. To our knowledge, this is the only case in which the skin of the free flap of a COVID-19 positive patient was necrosed almost entirely subsequently, while the subcutaneous fat was relatively preserved.

Reconstructing abdominal wall defects with a free composite tissue flap:A case report

BACKGROUND Reconstructive repair of huge full-thickness abdominal wall defects following debridement for abdominal electric burns remains a clinically challenging task.An ideal abdominal wall repair means a re-closure of the defected abdominal wall with pedicled neurovascular myofascial flaps,restoration of the abdominal wall integrity,and maintenance of the abdominal wall muscle tension to prevent the occurrence of abdominal wall hernia.When treating huge full-thickness defects,composite autologous tissue flaps are a good option for the repair.CASE SUMMARY This study reported the case of a 43-year-old male patient suffering from fullthickness abdominal wall defects complicated with necrosis of multiple bowel segments and duodenal leak following high-voltage burns involving the left upper limb and abdomen.After debridement for abdominal electric burns and end-to-end anastomosis for the necrotic bowels,reconstruction with acellular dermal matrix grafting and vacuum sealing drainage were performed for temporary abdominal closure.The remaining 18 cm×15 cm full-thickness abdominal wall defect was repaired using a combined anterolateral thigh and tensor fascia lata free flap.The proposed method achieved the functional reconstruction of the abdominal wall.CONCLUSION This approach restored the abdominal wall integrity,maintained certain muscle tension,avoided abdominal hernia,reached satisfactory aesthetic effect,and resulted in no complications in the grafting regions.

结合内增压技术的股前外侧跨区皮瓣修复肢体较大创面临床研究

目的:对比结合内增压技术的股前外侧跨区皮瓣与传统股前外侧皮瓣在修复肢体较大创面缺损中的临床疗效。方法:回顾性分析2018年5月—2022年5月浙江大学医学院附属邵逸夫医院收治的肢体较大创面缺损共38例患者(缺损面积达到11 cm×39 cm~16 cm×65 cm)的临床资料。按照修复方式的不同,将患者分为跨区皮瓣修复组(18例)和传统皮瓣修复组(20例)。跨区皮瓣修复组采用结合内增压技术的股前外侧穿支皮瓣联合旋髂浅动脉皮瓣(ALTP-SCIAP)治疗,传统皮瓣修复组采用单侧或双侧股前外侧皮瓣,必要时联合植皮。比较两组术后皮瓣存活情况、供区修复情况、并发症、患者满意度等。结果:跨区皮瓣修复组中,切取移植皮瓣18例次,瓣宽(9.9±2.0)cm,瓣长(44.2±3.5)cm,存活面积(343.2±79.9)cm^(2)。传统皮瓣修复组中,切取移植皮瓣29例次,瓣宽(11.0±2.8)cm,瓣长(21.7±3.2)cm,存活面积(186.4±49.2)cm^(2)。瓣长和存活面积跨区皮瓣修复组显著大于传统皮瓣修复组(t=22.365和8.345,均P<0.05)。跨区皮瓣修复组皮瓣供区采用直接缝合11例次,皮肤牵拉器辅助下缝合6例次,部分植皮修复1例次。传统皮瓣修复组皮瓣供区采用直接缝合12例次,皮肤牵拉器辅助下缝合11例次,部分植皮修复6例次。两组皮瓣供区修复的植皮率分别为5.6%(1/18)和20.7%(6/29),差异无统计学意义(χ^(2)=2.007,P>0.05)。跨区皮瓣修复组中出现并发症1例(5.6%),患者满意度达到94.4%;而传统皮瓣修复组中出现并发症7例35.0%,患者满意度为70.0%。相比传统皮瓣修复组,跨区皮瓣修复组并发症发生率降低(χ^(2)=4.942,P<0.05),患者满意度升高(χ^(2)=4.448,P<0.05)。结论:与传统股前外侧皮瓣比较,结合内增压技术的股前外侧跨区皮瓣切取面积更大,皮瓣供区大多可Ⅰ期直接缝合,不需要植皮修复,并发症更少,患者满意度更高。

不同皮瓣修复术对口腔颌面部肿瘤术后缺损手术时间及口腔功能指标的影响

目的:分析口腔颌面部肿瘤术后缺损患者行不同皮瓣修复术治疗的效果。方法:选择口腔颌面部肿瘤术后缺损患者58例,随机分为对照组和观察组,各29例。两组均施以皮瓣修复手术治疗,对照组胸大肌位置选择皮瓣,观察组为股前外侧皮瓣,比较不同部位皮瓣的效果差异。结果:观察组并发症总发生率低于对照组;手术时间、拔除胃管时间、经口进食时间、皮瓣愈合时间短于对照组;皮瓣制作+显微吻合时间长于对照组;外形修复、正常进食、口腔开合功能、口腔容纳水测试、正常吞咽、咀嚼功能、语言表达能力、正常咬合功能分数,皮瓣成活率和修复满意度高于对照组(P<0.05)。结论:口腔颌面部肿瘤术后皮瓣修复患者行不同皮瓣修复术的效果存在差异,股前外侧皮瓣相对比胸大肌皮瓣更具备优势,可缩短手术时间,改善口腔功能,安全度、患者满意度较高。

激光多普勒在游离股前外侧皮瓣血运监测中的临床研究

目的应用激光多普勒监测游离股前外侧皮瓣血流灌注情况,探索游离股前外侧皮瓣术后血流灌注规律,并研究其在游离股前外侧皮瓣坏死预测中的可行性。方法分析2018年1月-2019年12月采用游离股前外侧皮瓣移植修复手部创面患者资料56例,术后均采用激光多普勒监测法监测皮瓣血流灌注情况。激光多普勒监测指标为术中供区皮瓣切取前、术后即刻、术后第1天、3天、5天、7天、9天的皮瓣血液灌注。结果术后第9天,56例皮瓣全部成活,其中2例在术后4 h发生动脉危象,探查后危象解除;8例发生静脉危象,处理后危象解除,皮瓣顺利成活。与皮瓣断蒂前相比,术后即刻及术后1~5 d血液灌注明显加快(P<0.01),血液灌注在术后第5天达到高峰,随后呈现下降趋势。结论激光多普勒能较早发现游离皮瓣血管危象,临床医生可更加了解皮瓣情况。游离皮瓣灌注总体呈现先上升后下降的趋势,为临床用药及护理工作提供参考依据。

多种模式疼痛护理干预在游离股前外侧皮瓣修复上肢创面中的应用

目的探讨分析多种模式疼痛护理干预在游离股前外侧皮瓣修复上肢创面中的应用价值。方法选取2020年8月至2023年8月我院收治的100例游离股前外侧皮瓣修复上肢创面患者,以数字表法分组,随机分为对照组(常规护理干预)和观察组(多种模式疼痛护理干预)2组,各50例,对比分析两组干预效果。结果术后6 h、12 h、24 h及48 h观察组疼痛数字评分法(NRS)评分低于对照组(P<0.05);干预后观察组较对照组日常生活活动能力量表(ADL)、健康调查见表(SF-36)评分更高(P<0.05);观察组较对照组满意度高(P<0.05)。结论多种模式疼痛护理干预用于游离股前外侧皮瓣修复上肢创面患者护理中能有效减轻其疼痛程度,提高日常生活活动能力、生活质量,患者对护理也更为满意,值得推广。

股前外侧皮瓣在头面部较大软组织缺损修复中的应用

目的:探讨股前外侧游离皮瓣修复头面部软组织缺损的临床应用效果。方法:选取2018年8月-2022年10月就诊于笔者科室的头面部皮肤及皮下组织缺损并行游离皮瓣修复术的患者(其中男4例,女2例,年龄46~62岁)进行回顾性分析,头面部软组织缺损面积为8.0 cm×5.0 cm~18.0 cm×14.0 cm,部分可见颅骨及钛网外露。彻底清创后,切取合适大小股前外侧游离皮瓣予以封闭创面,切取皮瓣面积为13.0 cm×10.0 cm~20.0 cm×15.0 cm。大腿供皮区予以直接间断缝合或刃厚游离皮片移植加压包扎。术后随访3个月~1年,观察皮瓣存活、瘢痕、功能恢复及满意度情况。结果:6例移植皮瓣全部存活,外观良好,无明显瘢痕增生、牵拉移位及功能障碍,患者满意度良好。结论:对于头面部较大软组织缺损患者,采用股前外侧游离皮瓣移植是一项临床可行且效果良好的修复方式。

腓肠神经营养血管皮瓣修复术治疗开放性踝关节骨折的效果

目的观察腓肠神经营养血管皮瓣修复术治疗开放性踝关节骨折并发组织缺损的效果及对血流动力学、外观满意度的影响。方法以2021年1月至2023年1月医院收治的80例踝关节骨折并发组织缺损患者为研究对象,根据不同手术方法分为两组,各40例。A组接受腓肠神经营养血管皮瓣修复术,B组接受股前外侧皮瓣移植术。比较两组皮瓣肿胀程度、手术前后足部血流动力学[内径、收缩期峰值流速(PSV)、血管舒张期低值流速(EDV)]水平、手术前后足部功能、外观满意度及并发症状况。结果A组皮瓣肿胀、治疗效果优于B组,差异有统计学意义(P<0.05)。与B组相比,术后3个月,A组PSV、内径、EDV指标较高,差异有统计学意义(P<0.05)。A组术后6个月足部功能评分高于B组(P<0.05)。与B组相比,A组术后3、6个月外观满意度评分高(P<0.05)。A组并发症发生率与B组比较,差异无统计学意义(P>0.05)。结论腓肠神经营养血管皮瓣修复术治疗开放性踝关节骨折并发组织缺损,可改善术后血流流速和足部功能,患者外观满意度较高,皮瓣肿胀程度减轻。

修薄股前外侧穿支皮瓣修复四肢皮肤软组织缺损25例

目的探讨修薄的股前外侧穿支皮瓣修复四肢皮肤软组织缺损的临床疗效。方法选取2020年1月-2021年12月收治的四肢皮肤软组织缺损患者25例,所有患者均接受修薄的股前外侧穿支皮瓣修复,分析整体预后情况。结果术后25例皮瓣均成活,其中4例皮瓣远端伴有小面积表皮坏死,经换药等对症干预后,愈合良好。术后随访3~18个月,所有患者局部移植皮瓣外形可,无臃肿,质地柔软,有弹性,肘、腕以及踝关节屈、伸功能不受限。供区愈合情况良好,无明显瘢痕增生。结论四肢皮肤软组织缺损予以修薄的股前外侧穿支皮瓣修复,能有效促进移植部位缺损组织恢复,且成活率高。

股前外侧游离皮瓣修复治疗足部皮肤软组织缺损的效果及对皮瓣成活率的影响

目的探究股前外侧游离皮瓣修复治疗足部皮肤软组织缺损的临床效果。方法前瞻性单纯随机选取2018年7月—2023年8月南京医科大学附属逸夫医院120例足部皮肤软组织缺损患者为研究对象,按照不同治疗方法分为两组,各60例。对照组施以常规治疗,观察组施以股前外侧游离皮瓣修复治疗,比较两组患者皮瓣成活率、血管危象发生率与足部功能评分。结果观察组皮瓣成活率[96.67%(58/60)]高于对照组[81.67%(49/60)],差异有统计学意义(χ^(2)=6.988,P=0.008)。观察组血管危象发生率[3.33%(2/60)]低于对照组[16.67%(10/60)],差异有统计学意义(χ^(2)=5.926,P=0.015)。治疗1个月、3个月后,观察组足部功能评分高于对照组,差异有统计学意义(P均<0.05)。结论足部皮肤软组织缺损后尽早采用股前外侧游离皮瓣修复治疗,可提高皮瓣存活率,降低血管危象发生率,改善足部功能,临床疗效显著。

股前外侧Flow-through皮瓣修复下肢大面积缺损合并主干动脉缺损

目的探讨应用股前外侧Flow-through皮瓣修复下肢大面积缺损合并主干动脉缺损的临床疗效。方法2017年9月-2022年3月,应用股前外侧Flow-through皮瓣修复下肢大面积缺损并主干动脉缺损10例,其中合并胫后动脉缺损7例,胫前动脉缺损3例。一期行骨折外固定,VSD覆盖创面,二期行股前外侧Flow-through皮瓣修复术。结果10例皮瓣均成活,1例皮瓣远端少许坏死,经换药后伤口愈合,2例术后出现静脉危象,探查后皮瓣成活。随访8~24个月,平均15个月,皮瓣外观质地良好,5例因皮瓣臃肿行皮瓣修整。供区除伤口瘢痕及色素沉着外,未出现功能影响等并发症。结论股前外侧Flow-through皮瓣穿支可靠,血管蒂长,轴心血管管径粗,可重建主干血管,是修复下肢大面积缺损合并主干动脉缺损的较好选择。

Application of Microsurgery in Facial Trauma Reconstruction

This article is to review the role of microsurgery in facial trauma reconstruction. Microsurgery was developed since 1960s and had been applied on facial trauma from 1970s to treat amputated scalp, nose, ear and lip. Microsurgical replantation of scalp and small parts of face restores function and achieves aesthetic results, but small size of vessels and venous drainage problems are most technical challenging. In this article, we reviewed many talented authors’ work to solve those problems in facial tissue replantation. If defects are huge, we need microsurgical free flaps for reconstruction. The current workhorse is anterolateral thigh flap and we reviewed the versatility and new concepts of the flap. Development of perforator flaps was another milestone of flap reconstruction because of better cosmetic result and lower donor site morbidity. We reviewed the concepts, history and application of perforator flaps. Finally, facial replantation developed in recent 5 years to treat extremely large facial defects which cannot be reconstructed with microsurgical flaps and traditional flaps alone. The task is complex and needs a large team to support the whole procedure. We also reviewed the facial allotransplantation, which is the ultimate application of microsurgery in facial trauma reconstruction.

股前外侧皮瓣复合个性化钛网支架在上颌骨缺损修复中的应用

目的:探讨股前外侧皮瓣联合3D打印个性化设计的钛网支架对于上颌骨缺损修复的临床效果。方法:对本院2022年采用股前外侧皮瓣复合个性化钛网支架修复的8例上颌骨缺损患者进行回顾性分析。结果:8例患者所有组织瓣均成活良好,术后面部外形对称,口鼻腔及口腔上颌窦完全封闭,术后发音清楚,与人交流无障碍,面部外形及口腔功能患者较为满意。结论:股前外侧皮瓣复合个性化钛网支架的手术方式修复上颌骨缺损,能够获得较为满意的面部外形与功能,有效地恢复患者吞咽以及语言功能,提高了患者术后的生存质量,可以作为上颌骨缺损修复的一种有效手段。

带蒂股前外侧皮瓣在下肢软组织肉瘤术后修复软组织缺损的疗效

目的 探讨带蒂股前外侧皮瓣在下肢软组织肉瘤术后修复软组织缺损的疗效。方法 2021年8月-2022年4月,收治11例下肢软组织肿瘤患者,按手术RO标准切除肿瘤,同时切取带蒂股前外侧皮瓣修复皮肤软组织缺损。皮瓣切取范围:12 cm×10 cm~15 cm×14 cm。供区直接拉拢缝合或通过植皮覆盖创面。结果 11例皮瓣均顺利成活;供区一期愈合,植皮成活良好。术后随访6~10个月,肿瘤无复发,皮瓣外观及下肢功能均满意。结论 带蒂股前外侧皮瓣适用于修复下肢软组织肉瘤术后软组织缺损。

术前应用低分子肝素钙在游离股前外侧皮瓣移植术中的临床价值分析

目的探讨术前12 h应用低分子肝素钙在游离股前外侧皮瓣移植术中的临床疗效。方法选取50例手、足部皮肤软组织缺损行游离股前外侧皮瓣移植术修复的患者为研究对象,随机分成观察组(26例)和对照组(24例)。观察组术前12 h开始使用低分子肝素钙,术后4 h继续常规使用;对照组术后4 h开始常规使用低分子肝素钙。比较两组术后皮瓣成活率、皮瓣血管危象发生率及术后出血性事件发生率。结果随访3个月后,两组共行游离皮瓣52块,其中2例为双侧股前外侧皮瓣移植。①皮瓣成活率:观察组26例患者中,25例皮瓣全部成活,1例出现皮瓣尖端部分坏死,皮瓣成活率为96.2%。对照组24例患者中,所有皮瓣均成活,未出现皮瓣坏死现象,皮瓣成活率为100.0%。两组皮瓣成活率比较差异无统计学意义(P>0.05)。②血管危象发生率:观察组26例患者均未出现血管危象并探查情况,血管危象发生率为0;对照组1例患者发生2次血管危象,经2次探查后成活,其他23例患者均未发生血管危象,血管危象发生率为4.2%,两组血管危象发生率比较差异无统计学意义(P>0.05)。两组均未发生术后出血性事件。结论术前12 h开始使用低分子肝素钙对比术后4 h开始使用低分子肝素钙对皮瓣成活率、皮瓣血管危象发生率的影响无明显差异,术前12 h或术后4 h开始使用低分子肝素钙均不会增加术后出血性事件发生率。