胸腰椎骨質(zhì)疏松骨折處理

1、胸腰椎骨質(zhì)疏松骨折處理Approximately 2 million people sustain an osteoporotic fracture in the United States each year; 25% of those are vertebral compression fractures. Most fractures can be treated nonoperatively, using a combination of bracing, physical therapy, and pain medications.Surgical treatment may be

2、considered for patients with severe pain or who have failed nonoperative options. Surgical treatment options include vertebroplasty and kyphoplasty, which involve the injection of bone cement (polymethylmethacrylate) to augment vertebral bone strength; kyphoplasty adds the in?ation of a balloon tamp

3、 to help reduce the fracture and create a space for the cement. The risk of cement extravasation is relatively high, especially during vertebroplasty; however, the incidence of symptomatic leaks is relatively low. Overall, both procedures offer low complication rates, excellent pain relief, and impr

4、oved function after vertebral compression fractures. Semin Spine Surg 22:58-66 ? 2010 Elsevier Inc. All rights reserved.KEYWORDS vertebral compression fracture, osteoporosis, vertebroplasty, kyphoplasty, man- Agement在美國，每年大約有200萬人發(fā)生骨質(zhì)疏松骨折，其中25是椎體壓縮性骨折。大多數(shù)骨折可以采用支具、理療、止痛藥等聯(lián)合的非手術(shù)治療，對于嚴重疼痛或非手術(shù)治療失敗者可以采用手

5、術(shù)治療。手術(shù)治療包括后凸成形和椎體成形術(shù)，通過注入骨水泥（聚甲基丙烯酸甲酯）增強椎體。后凸成形通過球囊擴張來復(fù)位骨折，并為骨水泥制造一個空間。骨水泥滲漏的機會比較高，特別是椎體成形術(shù)。但產(chǎn)生癥狀者較少?？傮w而言，兩種手術(shù)的并發(fā)癥都很低，都能顯著緩解疼痛，提高椎體壓縮性骨折的功能。關(guān)鍵詞：椎體壓縮性骨折，骨質(zhì)疏松，椎體成形術(shù)，后凸成形術(shù)，治療。Spectrum of Disease Senile or insuf?ciency fractures are primarily the result of osteopenia and osteoporosis, de?ned by the Worl

6、d Health Organization as a t score less than 1 and less than 2.5, respectively. 1 The t score is the number of standard devia- tions between the patients bone mineral density (BMD) and that of the reference value of the BMD of a young adult. It is believed that osteoporosis develops because of the u

7、ncou- pling of the normal balance between bone resorption and new bone formation, 2 resulting in a net decrease in bone mass. Osteoporosis can be primary, secondary, or idiopathic. Primary osteoporosis, the most common form, can be divided into 2 subgroups, senile and postmenopausal. Senile osteopo-

8、 rosis is a slow, gradual loss of bone mass, and is considered a normal part of the aging process. Postmenopausal osteoporosis is a rapid decrease in BMD seen after a woman enters meno- pause. Secondary osteoporosis can be related to a systemic disease, such as diabetes, or tomedications, such as co

9、rticosteroids or antiseizuremedications. Idiopathic osteoporosis, as the name implies, has no identi?able cause.疾病概況世界衛(wèi)生組織定義當t值小于1時，為骨質(zhì)疏松，其首發(fā)癥狀常是骨折。t值是患者的骨密度（BMP與年輕成年人骨密度參考值的標準差。骨質(zhì)疏松是由于骨吸收與骨形成之間失衡，從而引起骨量減少。骨質(zhì)疏松分為原發(fā)性、繼發(fā)性和特發(fā)性。原發(fā)性骨質(zhì)疏松是最常見的類型，可再分為老年性和絕經(jīng)后。老年性骨質(zhì)疏松骨量丟失逐漸發(fā)生，進展較慢，為老年的正常改變。絕經(jīng)后骨質(zhì)疏松在停經(jīng)后骨密度迅速下降。

10、繼發(fā)性骨質(zhì)疏松多源于系統(tǒng)性疾?。ㄈ缣悄虿。┗蛩幬铮ㄈ缙べ|(zhì)激素或抗癲癇藥物）。特發(fā)性骨質(zhì)疏松正如其名所示，沒有明確的原因。國際骨質(zhì)疏松基金會估計，美國有800萬婦女和200萬男性患有骨質(zhì)疏松癥，另有3400萬人骨量減少。大約一半的婦女和四分之一的男性在年齡超過50歲后會發(fā)生骨質(zhì)疏松性骨折，其中大約200萬發(fā)生骨折，包括30萬的髖部骨折和55萬的椎體壓縮骨折（VCF）。VCF目前的直接醫(yī)療消費大約為170億美元，到了2025年增加到253億美元，2040年將達到500億美元。每年因這些骨折而住院的人數(shù)超過40萬。Approximately 2 million people sustain an o

11、steoporotic fracture in the United States each year; 25% of those are VCFs, which can be symptomatic or asymptomatic. Asymptomatic VCFsmay be identi?ed incidentally on imaging studies or by the increasing kyphotic posture of the patient. Approximately one-third (23%-33%) of patients with VCFs presen

12、t with acute pain. 6 Both symptomatic and occult of VCFs may occur spontaneously or may be the result of low-energy trauma, such as a fall. Some of the more common risk factors for VCF include female gender, increased age, smoking, and frequent falls (Table 1). 7-10 In men, a low testoster-one level

13、 is a substantial risk factor.美國每年骨質(zhì)疏松骨折的人數(shù)約為200萬，25為VCF，其中有些有癥狀，有些沒有癥狀。無癥狀性骨質(zhì)疏松可因偶然拍片或進行性后凸發(fā)現(xiàn)。約有三分之一的VCF患者出現(xiàn)急性疼痛。無癥狀或癥狀性VCF均可由低能量損傷（如跌倒）引起。發(fā)生VCF的危險因素包括：女性，老齡，吸煙，頻繁跌倒等（表1）。對于男性，睪酮低下是重要的危險因素。VCF可對患者的總體健康狀況產(chǎn)生嚴重的影響。據(jù)估計，每骨折一次，存活率下降9，同時也使患者的呼吸能力下降。此外，VCF的患者，再骨折的機會是沒有骨折者的5倍，其中20在1年內(nèi)會再出現(xiàn)VCF，50在3年內(nèi)會出現(xiàn)VCF。這種

14、高骨折風險與初始VCF后椎體前側(cè)楔變從而引起進行性后凸有關(guān)。由于進行性后凸，身體的重心前移，從而使負荷由椎體前方傳導(dǎo)，在椎體上形成異常的壓力，從而形成新的骨折。VCF患者髖部骨折的發(fā)生率也將增加兩倍。VCF后第一年的死亡率達到20%。3年死亡率46.1%，5年死亡率69.1%，7年死亡率則達89.5%，大致為對照組的兩倍。Diagnosis and Evaluation VCFs should be suspected in at-risk individuals with axial back pain or increasing kyphotic posture. Rarely, pati

15、ents may have radicular- or stenotic-type symptoms. Evaluation begins with a complete medical history, with attention to any history of cancer, and a thorough physical examination, including assessment of lower extremity neurologic function. The initial imaging study is conventional radiographs, whi

16、ch will frequently show the fracture; standing radiographs are not usually required, but they may be useful in assessing the patients overall kyphosis and sagittal balance. In some cases, computed tomography imaging may be needed to visualize fractures that are suspected but not seen on poor-quality

17、 radiographs or for the evaluation of fractures in the upper thoracic spine, which is known to be dif?cult to evaluate with conventional radiographs. Computed tomography may also assist in preoperative planning, speci?cally in terms of evaluating the integrity of the posterior wall of the vertebral

18、body. Magnetic resonance imaging (MRI) helps to distinguish new, acute fractures from older, healed ones. Acute fractures show increased signal intensity on T2-weighted, fat-suppressed T2-weighted, and short tau inversion recovery images. If the patient is unable to obtain an MRI study, a bone scan

19、may be used, but there may be a lag time between fracture onset and a positive ?nding on a bone scan, leading to a possible falsenegative result. The acuity of the fracture is an important distinction: some authors believe that healed fractures are less likely to respond to vertebral augmentation su

20、rgery.18 MRImay also be helpful in evaluating any compression of the neural elements, whether from retropulsion of the posterior wall or from narrowing of the neural foramen. Diffusion-weighted images may help to distinguish pathologic from benign compression fractures. 19 A dual-energy x-ray absorp

21、tiometry scan should be performed to assess the patients BMD.Medical and/or cardiology consults should be obtained as appropriate if surgery is planned. Consulting a pain management specialist may also be helpful.診斷與評估背痛和進行性后凸應(yīng)懷疑椎體壓縮性骨折?；颊吆苌儆懈曰颡M窄癥狀。評估要從完整的病史開始，注意任何癌癥史，并做全面的體格檢查，包括下肢神經(jīng)功能。常規(guī)X線片通?？梢燥@示

22、骨折，站立位不是必須的，但有助于評估患者的整體后凸情況及矢狀面平衡。對某些X線不清楚而懷疑骨折或普通X線難以辨認的上胸椎患者，CT有助于看清骨折。CT也有助于術(shù)前評估，特別是椎體后壁的完整性。MRI有助于區(qū)別新鮮骨折還是陳舊骨折。急性骨折在T2加權(quán)、T2加權(quán)壓脂相、短梯度翻轉(zhuǎn)還原相上表現(xiàn)為高信號。如果不能做MRI，也可以做一個骨掃描，但由于骨折發(fā)生與骨掃描陽性之間有一個時間遲滯現(xiàn)象，可能出現(xiàn)錯誤的陰性結(jié)果。鑒別出新鮮的骨折十分重要，因為治愈的骨折對椎體增強無反應(yīng)。MRI也有助于神經(jīng)受壓情況，如椎體后壁骨折塊移位或椎間孔狹窄。彌散加權(quán)像有助于區(qū)別是不是病理性骨折。還必須做一個雙能X線吸收掃描來評

23、估一下患者的骨密度。如果計劃手術(shù)，要請內(nèi)科或心血管科會診，疼痛專家會診也是很有用的。Treatment NonoperativeInitial treatment of VCFs is nonoperative: a combination of pain medication, physical therapy, and possibly bracing. Pain medications should be multimodal and may include combinations of narcotics, nonsteroidal anti-in?amatory medicatio

24、ns, antidepressants, and neuropathic agents. Each of these classes ofmedications has substantial side-effect pro-?les, including sedation from narcotics and gastrointestinal and cardiac effects from nonsteroidal anti-in?amatory medications, which are accentuated in elderly patients. A pain managemen

25、t specialist and the patients primary care physician should be involved in the prescribing of any of these medications.治療非手術(shù)治療VCF的首選治療是非手術(shù)治療，止痛藥、理療、支具相結(jié)合。止痛藥有多種機制，包括麻醉藥、非甾體抗炎藥、抗抑郁藥、神經(jīng)營養(yǎng)藥等。每種藥都有一定的副作用，包括麻醉藥的鎮(zhèn)靜作用、非甾體抗炎藥的胃腸道反應(yīng)和心血管反應(yīng)，尤其是老年人。疼痛專家和患者的初級治療師也要參與其中。Physical therapy has been shown to improve

26、a patients pain and to reduce the risk of future fractures. 20,21 Initially, therapy should focus on core strengthening to improve posture and spinal mechanics. 22 Focusing on strengthening the back extensors may help to decrease loads on the spine. 21 Proprioceptive training may help reduce the ris

27、k of fall and理療可以減輕疼痛，并減少再發(fā)骨折的危險。最初的治療著重改進姿勢和脊柱力學(xué)。強化背伸肌有助于減少脊柱上的負荷。本體覺的訓(xùn)練有助于減少跌倒，防止更多的損傷。The use of a bracemay help to immobilize and support the spine, decreasing the pain associatedwith the fracture. Braces may also help to improve posture, decreasing some of the load on the spine. Multiple bracin

28、g options are available, including Jewett and cruciform anterior spinal hyperextension braces, thoracolumbosacral orthoses, and posture-training support orthoses. Patient compliance with bracing may be dif?cult because the braces can be uncomfortable and hard to put on and take off. In addition, pat

29、ients who are overweight or who have a severe deformitymay be dif?cult to ?t with braces.支具有助于制動，支持脊柱，減少骨折引起的疼痛。支具也有助于改善姿勢，減少脊柱上的負荷。目前有多種支具可選，包括Jewett支具、十字形過伸支具、胸腰骶支具、姿勢訓(xùn)練支具等?；颊呖赡懿辉概宕髦Ь?，因為支具可能不舒服，穿脫也很困難。另外，體重過大或嚴重畸形者，也很難使用支具。Selective nerve root injections or spinal epidural injections may be helpfu

30、l for patients with fractures that compress the neural elements. Epidural injections may be particularly useful for patients with a retropulsed fragment invading the spinal canal but who are not good surgical candidates. Selective nerve root injections may be used for patients with radiculartype sym

31、ptoms.選擇性神經(jīng)阻滯或硬膜外阻滯對骨折伴有神經(jīng)受壓者是有用的。硬膜外阻滯對椎管占位但又沒有手術(shù)指征者特別有用，選擇性神經(jīng)根阻滯對有神經(jīng)根癥狀者有效。In addition to treating the fracture, the clinician should address the patients osteoporosis or osteopenia. This treatment should be orchestrated in a multidisciplinary fashion, involving the surgeon, the patients primary c

32、are physician, and potentially an endocrinologist. Asmentioned previously, a dual-energy x-ray absorptiometry scan should be obtained to measure the patients BMD. The patients nutrition should be maximized, ensuring suf?cient intake of vitamin D (800-1000 IU/d)24 and calcium (1200 mg/d). 25 Medical

33、management may include the use of bisphosphonates, calcitonin, estrogen, raloxifene (a selective estrogen analog), and parathyroid hormone. Currently, the American Board of Obstetrics and Gynecology recommends prescribing one of these medications for any patient sustaining an osteoporotic fracture,

34、a woman with a t score of less than 2, or a patient with a t score of less than 1 with at least 1 associated risk factor. 26 Recently, a large, multicenter, prospective randomized control study evaluated the use of zoledronic acid (an intravenously administered bisphosphonate) after osteoporotic hip

35、 fractures and found a 35% reduction of risk for new fracture and a 28% reduction in mortality at 1.9 years. 27 Those authors noted relatively minor complications with the medication, including myalgia, pyrexia, and musculoskeletal pain. There were no episodes of jaw necrosis, and the rates of renal

36、 and cardiac events were in both the treatment and placebo groups.治療骨折，臨床醫(yī)師要確定有無骨質(zhì)疏松或骨質(zhì)減少。治療必須多學(xué)科綜合配合，包括外科醫(yī)師、患者的初級治療師、也可能要內(nèi)分泌醫(yī)師。正如前文所提的，要做雙能X線吸收掃描，以測定患者的BMD.患者的營養(yǎng)要充分，保證每天攝入8001000IU的維生素D和1200mg的鈣。內(nèi)科治療包括雙膦酸鹽、鈣、雌激素、雷洛昔芬（一種選擇性雌激素類似物），甲狀旁腺素等。最近，美國婦產(chǎn)科委員會提出，一旦有骨質(zhì)疏松骨折或T值小于2的婦女，或T值小于1同時至少有一個危險因素者應(yīng)開始服藥治療。最近一

37、項大型、多中心、前瞻性隨機對照研究發(fā)現(xiàn)，唑來膦酸（一種靜脈用雙膦酸鹽）用于骨質(zhì)疏松髖部骨折，可以降低35的再骨折發(fā)生率，在年可降低28的死亡率。這些作者提到了少量的并發(fā)癥，包括肌痛，發(fā)熱、骨骼肌肉疼痛等。沒有出現(xiàn)下頜壞死這種少見情況。治療組與安慰劑對照組的腎臟與心臟并發(fā)癥均有發(fā)生。OperativeGiven that most VCFs occur in elderly patients without neurologic de?cits who havemedical comorbidities and osteopenia or osteoporosis, conventional s

38、urgical techniques, such as instrumented fusion, have been avoided for the treatment of VCFs. However, with the advent of percutaneous vertebral augmentation, such patients have become candidates for surgical intervention. There are 2 basic forms of percutaneous vertebral augmentation, vertebroplast

39、y and kyphoplasty. Both procedures are similar in position and approach, but they have technical differences. Vertebroplasty was introduced ?rst in France in 1984 and was described in 1987 by Galibert et al. 28 It was not introduced in the United States until 1994. 29 Vertebroplasty involves the inj

40、ection of cement, usually polymethylmethacrylate (PMMA), into the fracture site. Recently, kyphoplasty has been introduced. This procedure involves the in?ation of a balloon-type bone tamp before the injection of the PMMA, which may allow for the partial reduction of the fracture and the creation of

41、 a void into which the cement can be inserted under low pressure.手術(shù)治療由于大多數(shù)VCF沒有神經(jīng)損害，同時有內(nèi)科并存病和骨質(zhì)疏松，傳統(tǒng)的外科手術(shù)如器械固定融合并不合適。隨著經(jīng)皮椎體增強技術(shù)的出現(xiàn)，這類病人可以進行外科干預(yù)。經(jīng)皮椎體增強技術(shù)有兩種方式：椎體成形術(shù)和后凸成形術(shù)。兩種手術(shù)的體位和入路相同，但有技術(shù)上的不同。椎體成形術(shù)1984年在法國開始應(yīng)用，1987年Galibert等首先報道。在美國，直到1994年后才開始應(yīng)用。椎體成形術(shù)是將骨水泥（通常是聚甲基丙烯酸甲酯，PMMA）注入骨折部位。近來，后凸成形術(shù)開始應(yīng)用，后凸成形術(shù)

42、是通過一個球囊進行擴張，使骨折部分復(fù)位，并制造一個空腔，這樣就可以在比較低的壓力下注入骨水泥。Indications for SurgeryThe indications for vertebroplasty and kyphoplasty in the treatment of VCFs include acute, painful, osteporotic or osteolytic VCFs; pathologic fractures in patients withmetastatic disease; painful vertebral hemangioma; and Kummell

43、s disease. 30,31 It is important that only symptomatic fractures be treated and not all fractures that are seen on imaging studies. 31 Most commonly, VCFs are treated acutely, although chronic fractures may also respond to treatment. The best method for differentiating acute or subacute VCFs from ch

44、ronic fractures is via the use of MRI and, speci?cally, fat suppressed T2-weighted or short tau inversion recovery sequence images. Fractures that show increased signal intensity (compatible with edema) on these pulse sequences are likely to be acute or subacute and have a high chance of responding

45、favorably to vertebral augmentation procedures in terms of pain relief.手術(shù)適應(yīng)癥椎體成形術(shù)和后凸成形術(shù)的手術(shù)適應(yīng)癥包括：急性、疼痛性骨質(zhì)疏松性椎體壓縮骨折；轉(zhuǎn)移癌引起的病理性骨折；痛性椎體血管瘤；Kummell氏病。只有有癥狀的骨折才需要治療，而不是所有影像所見的骨折都需要治療。雖然慢性骨折對治療也有效，但VCF大多在急性期治療。區(qū)別急性或亞急性骨折與陳舊性骨折的最好方法是MRI，特別是壓脂T2加權(quán)或短T翻轉(zhuǎn)恢復(fù)序列，在這些序列上信號增高的（可能有血腫），可能是急性或亞急性骨折，椎體增強的止痛效果較好。Contraindi

46、cations for vertebral augmentation include de?ciency of the posterior wall, local or systemic infection (sepsis), osteoblastic metastatic lesions, inability to obtain adequate intraoperative imaging, and advanced or multiple medical comorbidities. In addition, performing these procedures on fracture

47、s with severe collapse and vertebra plana may be technically challenging.椎體增強的禁忌癥包括：后壁不完整，局部或全身感染，成骨性轉(zhuǎn)移灶，術(shù)中無法提供影像支持，伴有多發(fā)或嚴重的內(nèi)科并存病。此外，在嚴重塌陷和扁平椎實施該手術(shù)也是一項技術(shù)挑戰(zhàn)。Surgical TechniquePatient positioning for vertebroplasty and kyphoplasty is similar. Patients are usually positioned prone on a radiolucent tabl

48、e. As with all prone patients, care should be taken to protect the eyes and to pad all bony prominences. In rare cases, patients may be positioned in the lateral position. Ideally, the back should be extended to facilitate reduction. Anesthesia may be general, sedation, or local, depending on the ci

49、rcumstance and the patients medical condition.外科技術(shù)椎體成形術(shù)和后凸成形術(shù)的體位相似?；颊咄ǔ８┡P于可透視床上，由于是俯臥位，要注意保護眼睛，并在骨突上置墊。少數(shù)情況下，也可以置于側(cè)臥位。背部過伸，以利復(fù)位。麻醉可用全麻、鎮(zhèn)靜或局部麻醉，取決于具體情況和患者條件。病人擺好體位后，先做個正側(cè)位透視，前后位要調(diào)整適應(yīng)病椎的前凸或后凸，以獲得真正的前后位。如果位置正確，椎體上下終板顯示清晰，雙側(cè)椎弓根對稱，與棘突的距離相等。良好的影像十分重要，如果圖像不滿意就不應(yīng)進行手術(shù)。用一臺還是兩臺透視機取決于條件和外科醫(yī)生的喜好。兩臺透視機有助于減少手術(shù)時間和減

50、少骨水泥滲漏的機會。After the patient is successfully positioned, the vertebra to be augmented is localized. The anterior vertebral body can be approached via a transpedicular, extrapedicular, or posterolateral approach. The choice of approach should be identi?ed preoperatively, based on the imaging studies a

51、nd location of the fracture. The transpedicular approach is typically used for vertebrae between T10 and L5. This approach may be disadvantageous for patients with small pedicles or for those whose vertebrae are collapsed below the level of the pedicle. The extrapedicular approach is usually used fo

52、r higher thoracic levels or vertebrae with small pedicles. It has the advantage of allowing more medial placement of the working cannula. The posterolateral approach is reserved for lumbar vertebrae with extensive collapse or small pedicles, factors which would make the standard transpedicular appro

53、ach technically challenging.在病人擺好體位后，要增強的椎體要定位好?？赡芡ㄟ^經(jīng)椎弓根、椎弓根外、后外側(cè)入路到達椎體前側(cè)。入路的選擇要根據(jù)影像和骨折的部位，術(shù)前就確定好。經(jīng)椎弓根入路常用于T10L5，對于椎弓根較小或椎體爆裂骨折位于椎弓根平面下者不合適。椎弓根外入路用于高位胸椎及椎弓根較小者，其優(yōu)點在于套管可以更偏向內(nèi)側(cè)放置。后外側(cè)入路用于腰椎嚴重爆裂或小椎弓根或采用標準經(jīng)椎弓根困難者。For the transpedicular approach, an incision is made approximately 2-3 cm lateral from midli

54、ne, in line with thempedicle. The appropriate trocar or needle is selected and,munder ?uoroscopic guidance, it is positioned on the superolateral corner of the pedicle. The trocar is advanced using?rm but controlled pressure; frequent images are obtainedmto con?rm location. The trocar should be angl

55、ed slightly medial, but care should be taken that the needle does notcross the medial border of the pedicle on the AP image until it has reached the posterior aspect of the vertebral body and the end of the pedicle on the lateral view. If the trocar is noted to cross the medial border before this st

56、age, a medial breach should be suspected, and the trocar should be withdrawn and redirected. After the trocar has entered the vertebral body, it should continue to be angled medially and should approach, but not cross, the midline. An oblique view directed straight down the pediclemay be helpful for

57、 con?rming the position of the trocar within the pedicle. This view is obtained by bringing the ?uoroscopy unit approximately 10 off the midline to provide a view line with the path of the pedicle.采用經(jīng)椎弓根入路，在中線外約23cm處椎弓根線做切口。選擇合適的套管針透視下置于椎弓根的外上角，穩(wěn)穩(wěn)控制前進，多透視以確定位置。套管針要輕度偏向內(nèi)側(cè)，但要注意，在側(cè)位上到達椎體后壁、椎弓根末端之前在前后位上

58、不要超過椎弓根的內(nèi)側(cè)界。如果在此之間套管就超過了椎弓根的內(nèi)側(cè)界，要考慮內(nèi)側(cè)壁穿破，套管針要取出重新定向。一旦套管針進入椎體，要盡量向內(nèi)側(cè)傾斜，但不要超過中線。將球管偏離中線10使球管方向與椎弓根方向一致的斜位片有助于確定套管針是否位于椎弓根內(nèi)。As mentioned previously, the extrapedicular approach is typically used in the mid to upper thoracic spine. A transpedicular approach at these levels usually results in an unaccep

59、tably lateral placement of the trocar. To perform the extrapedicular approach, the trocar is positioned just superior and lateral to the pedicle, and medial to the head of the rib. Occasionally, it is necessary to cannulate through the rib head. The starting point should be at or anterior to the lev

60、el of the spinal canal on a lateral image, which minimizes the risk of spinal canal violation. Care should be taken not to slide inferior or superior off the rib head, where plunging with the trocar risks injuring the lung.如前所述，椎弓根外入路主要用于中至上胸椎，在這些部位，經(jīng)椎弓根入路套管針的側(cè)方位置無法接受。要采用椎弓根外入路，套管針必須位于椎弓根的外上方，并位于肋骨頭