複雑型の脾損傷（IIIｃ）があり，脾周囲には不均一な（血腫を含む）腹水がある（※）．図３でdensityは59.6HUで，50HU以上は血腫を意味するといわれる．図２〜図９の△は脾臓外に位置し，脾臓実質よりdensityが高く，血管の存在しない部位だからextravasationであり，早急に塞栓術か手術による止血操作を要する．しかし，extravasationの所見を見落とされ，保存的に経過観察され，Hbが5.6g/dlまで低下し4単位の輸血を要した．造影CTでextravasationを認めれば，手術をさけるため，または輸血量を最小限度に抑えるためにも血管造影と塞栓術を施行すべきである．

参考症例（脾損傷 II：被膜損傷，AAST spleen injury scale grade II）．25歳女性，突き飛ばされて左側胸部と側腹部を打撲した．左上腹部痛が軽減せず救急搬送された．血圧：118/72mmHg，脈拍：86/分，左上腹部に圧痛，反跳痛と軽度の筋性防御がある．

肝臓と脾臓周囲に腹水があるが（※），脾臓周囲のはやや不均一で，血腫を含むと考えられる．図１〜図３の↑は正常な血管である．図３〜図６の，脾臓外側の△は脾実質よりdensityが高く大動脈と同等であり，正常にはそこにはこの大きさの血管は存在しないのでextravasationである．脾臓に明白な損傷は認めないので，II型被膜損傷である．血管造影でCT所見と一致するextravasationを認め（▲），スポンゼル細片で塞栓術を施行し止血に成功した．Hbは12.0g/dlから8.7g/dlまで低下したが輸血をせず保存的に治癒した．

文献考察：脾損傷例にTAEを積極的に応用してから保存的治療の成績が向上した．
１）J Trauma. 2006 Jul;61(1):192-8.
Nonoperative management of splenic injuries: improved results with angioembolization.
Gaarder C, Dormagen JB, Eken T, Skaga NO, Klow NE, Pillgram-Larsen J, Buanes T, Naess PA.

BACKGROUND: Nonoperative management (NOM) of patients with severe splenic injuries carries a significant risk of failure. We hypothesized that adding angiographic embolization (AE) to the NOM protocol would decrease the laparotomy rate, and increase the success rate of NOM and splenic salvage rate. METHODS: A protocol introducing AE in the treatment of splenic injuries was implemented. AE was performed in OIS splenic injury grades 3 to 5 and in all cases where signs of ongoing bleeding were encountered regardless of injury grade. Patients included in a prospective study during a 24-month period were compared with a historic control group. RESULTS: Group 1 (before AE) consisted of 69 patients with a mean Injury Severity Score (ISS) of 31, and group 2 (after introducing AE) included 64 patients with a mean ISS of 30. In group 1, 30 patients underwent immediate laparotomy (43%), and the NOM success rate was 79%. After introducing AE, 17 patients underwent immediate laparotomy (27%; p = 0.04), with a NOM success rate of 96% (p = 0.02). Overall splenic salvage rate increased from 57% to 75% (p = 0.02). Angiography was performed in 31 patients in group 2. Embolization was performed in 27 of these patients. AE failure rate was 4%. NOM was successful in 14 of 15 patients with OIS injury grades 4 and 5 after the introduction of AE (93%). CONCLUSION: A formal protocol adding mandatory AE to NOM for severe splenic injuries increased the percentage of patients in whom NOM was attempted, the NOM success rate, and the splenic salvage rate.PMID: 16832270

２）J Trauma. 2005 Mar;58(3):492-8.
Nonoperative management of blunt splenic injury: a 5-year experience.
Haan JM, Bochicchio GV, Kramer N, Scalea TM.

OBJECTIVES: The purpose of this study was to examine the success rate of nonoperative management of blunt splenic injury in an institution using splenic embolization. METHODS: We conducted a retrospective review of all patients admitted to a Level I trauma center with blunt splenic injury. Data review included patient demographics, computed tomographic (CT) scan results, management technique, and patient outcomes. RESULTS: A total of 648 patients with blunt splenic injury were admitted, 280 of whom underwent immediate surgical management. Three hundred sixty-eight underwent planned nonoperative management, and 70 patients were treated with observation, serial abdominal examination, and follow-up abdominal CT scanning. All were hemodynamically stable, with a 100% salvage rate. One hundred sixty-six patients had a negative angiogram, with a nonoperative salvage rate of 94%, and 132 patients underwent embolization, with a nonoperative salvage rate of 90%. Overall salvage rates decreased with increasing injury grade; however, over 80% of grade 4 and 5 injuries were successfully managed nonoperatively. The salvage rate was similar for main coil embolization versus selective or combined embolization techniques. Admission abdominal CT scan correlated with splenic salvage rates. Significant hemoperitoneum, extravasation, and pseudoaneurysm had acceptable salvage rates, whereas arteriovenous fistula had a high failure rate, even after embolization. CONCLUSION: Splenic embolization is a valuable adjunct to splenic salvage in our experience, allowing for the increased use of nonoperative management and higher salvage rates for American Association for the Surgery of Trauma splenic injury grades when compared with prior studies. Main coil embolization has a similar salvage rate when compared with other angiographic techniques. An arteriovenous fistula as a CT finding was predictive of a 40% nonoperative failure rate.PMID: 15761342