S1椎弓根螺钉结合髂骨板间螺钉治疗骶髂关节骨折脱位

目的 探索S1椎弓根螺钉结合髂骨板问螺钉治疗骶髂关节骨折脱位的临床疗效，评价两者结合对骶髂关节骨折脱位的治疗价值。方法 对11例骶髂关节骨折脱位患者用脊柱内固定系统(TSRH)之S1椎弓根螺钉结合髂骨板间螺钉进行固定，该组患者涉及骶髂关节的垂直移位及旋转的骨盆环变形，归于Tile分型的B类或C类骨盆损伤。11例患者均伴有前环损伤，其中9例予以加压钢板(smith nephew)内固定，余2例患者单纯采用后路手术内固定。结果 7例患者垂直移位完全复位，9例旋转畸形纠正，未发现感染及神经损伤等并发症。结论 S1椎弓根螺钉结合髂骨板问螺钉固定技术治疗骶髂关节骨折脱位，可获得即刻稳定性并良好地维持了复位的效果．这一混合技术对于涉及垂直及旋转损伤的骨盆环损伤有稳定的作用。     

Reduction and fixation of sacroiliac joint dislocation by the combined use of S1 pedicle screws and the galveston technique

STUDY DESIGN: This retrospective study was designed to analyze the results of the treatment with S1 pedicle screws and the Galveston technique of seven patients with sacroiliac dislocation. OBJECTIVES: To evaluate the effectiveness of the combined use of S1 pedicle screws and the Galveston technique for the treatment of sacroiliac dislocation. SUMMARY OF BACKGROUND DATA: Although several procedures for internal fixation of sacroiliac dislocation have been reported, there have been no reports discussing surgical treatment of sacroiliac dislocation by the combined use of S1 pedicle screws and the Galveston technique. METHODS: Seven patients with sacroiliac dislocation were treated with pedicle screws of S1 and iliac rod according to the Galveston technique. In the seven patients, the dislocation was associated with vertical displacement of the sacroiliac joint and rotational deformity of the pelvic ring. They were classified into Type-C pelvic disruption according to the Tile's classification. Three patients with disruption of the symphysis pubis underwent additional fixation of the symphysis using a dynamic compression plate. The remaining four patients were treated by the posterior procedure alone. RESULTS: The vertical displacement was completely reduced in five patients, and the rotational deformity was completely corrected in four patients. The reduction was maintained at the time of the final follow-up evaluation. There were no perioperative complications with the exception of late infection in one patient. CONCLUSIONS: The combined use of S1 pedicle screws and the Galveston technique provided immediate stability and sufficient reduction for sacroiliac dislocation in seven patients in this study. This hybrid internal fixation procedure is useful for reduction and fixation of sacroiliac dislocation associated with the vertical and rotational instability of the pelvic ring.     

骶髂拉力螺钉固定技术在骨盆后环损伤中的临床应用

目的 探讨应用骶髂拉力螺钉固定技术治疗骨盆后环损伤的适应证、手术方法及疗效。方法 1998年6月～2002年11月，对13例骨盆骶髂复合结构损伤患者采用后侧经骶髂关节的骶髂拉力螺钉固定方法治疗骨盆后环损伤，男10例，女3例；年龄21～49岁，平均37．5岁。通过影像学柱查明确13例患者有15侧骨盆骶髂复合结构损伤。按照AO骨盆环损伤方法分型：B型损伤6例．其中B2型4例，B3型2例；C型损伤7例．其中C1型2例，C2型3例，C3型2例。患者麻醉后俯卧位，行闭合或开放复位后用骶髂拉力螺钉固定。取髂骨翼后侧进钉点，根据S1椎体上缘和骶骨翼走行确定进钉方向。所有操作均在“C”型臂X线机透视下进行。结果 13例患者均获随访．随访时间6个月～4年6个月，平均19．7个月。手术平均时问为70min。13例共置入骶髂拉力螺钉21枚。患者在术后2-3周可持双拐下地行走，3～4个月双下肢可完全负重行走．并逐渐恢复体力劳动，未发生神经损伤及螺钉松动、断裂现象。腰骶及下肢活动接近正常。结论 骶髂拉力螺钉固定技术可使不稳定性骨盆后环损伤患者获得良好的即刻复位和固定，恢复骨盆的稳定性，适用于骶髂关节脱位及骶骨骨折的患者。     

拉力螺钉固定技术在骨盆后环损伤中的临床应用

目的探讨应用拉力螺钉固定技术治疗骨盆后环部损伤的适应证、手术方法及疗效。方法1998年8月至2005年12月，对47例骨盆骶髂结构复合损伤患者分别采用后侧经骶髂关节的拉力螺钉固定方法，后侧跨骶骨的髂-髂拉力螺钉固定方法及骶-髂拉力螺钉加髂：髂拉力螺钉固定方法治疗骨盆后环损伤，男31例，女16例；年龄18～53岁，平均32岁。通过影像学检查明确47例患者有60侧骨盆骶髂结构复合损伤。按照AO骨盆环损伤方法分型：B型损伤20例，其中B2型9例，B3型11例；C型损伤27例，其中C1型8例，C2型12例，C3型7例。患者麻醉后取俯卧位，行闭合或开放复位后用拉力螺钉固定。所有操作均在C型臂X线机透视下进行。结果47例患者均获随访，随访时间6个月至6年6个月，平均27．7个月。平均手术时间为80min。47例共置入骶髂拉力螺钉104枚。患者在术后2～3个月双下肢可完全负重行走，并逐渐恢复体力劳动。仅发生3枚螺钉松动，未发生神经损伤及螺钉断裂等并发症，腰骶及下肢活动接近正常。结论拉力螺钉固定技术可使不稳定性骨盆后环获得良好的即刻复位和固定，恢复骨盆环的稳定性，适用于骶髂关节脱位及骶骨骨折患者。     

骶髂关节经皮拉力螺钉固定钉道参数的解剖学测量

目的 为经S_1椎弓根水平骶髂关节拉力螺钉固定术提供应用解剖学依据.方法 2008年6月至2009年7月收集50个成人骨盆的螺旋CT扫描数据,重建骨盆三维模型,模拟经皮托力螺钉固定.测量S_1椎弓根的宽和高、骶髂关节拉力螺钉的进针点和进针方向、进针点至S_1椎体对侧前皮质和髂后上棘的距离.结果 S_1椎弓根的宽和高分别为(20.43±1.63)mm和(20.26±0.99)mm;2枚螺钉的进针点均在髂前上棘和髂后上棘的连线上方,至髂后上棘的距离分别为(49.87±6.80)mm和(51.11±7.15)mm.螺钉平行进入S_1椎弓根,与髂骨翼后外侧面垂直,与冠状面和欠状面的夹角分别为18.35°±5.20°和77.62°±3.98°.进针点到S1椎体对侧前皮质的距离分别为(76.08±4.32)mm和(77.62±3.98)mm.骶髂关节拉力螺钉的长度、S_1椎弓根的高度和宽度、进针点到髂后上棘的距离、进针点与冠状面的夹角在男女之间差异有统计学意义(P<0.05).结论 正常成人在S_1椎弓根水平均町置入2枚直径为6.5 mm的拉力螺钉,钉道参数的解剖学测量为骶髂关节拉力螺钉固定手术导航模板的设计提供了理论基础.     

Posterior bridging osteosynthesis for traumatic sacroiliac joint dislocation: a report of seven cases

Objective

To evaluate the long-term clinical and radiographic results in patients treated for 61C3-2 (OTA class) pelvic ring disruption with a posterior bridging sacroiliac fixation.

Design

Retrospective clinical and radiological study.

Setting

University Hospital.

Patients/participants

Between May 2002 and March 2003, seven patients with sacroiliac dislocation were treated with a technique developed for the treatment of pelvic injuries with vertical and horizontal instability.

Intervention

We applied spino-pelvic fixation techniques, using spine instrumentation, to stabilize an SI dislocation. This technique consists of two 5 mm diameter screws inserted into the S1 pedicle and S2 ala. A 5.5 mm rod joins the 2 sacral screws to two 7 mm screws placed into the posterior iliac crest and secured into the cancellous mass of the posterior ilium . The described technique stabilizes the SI-joint by performing a bridging osteosynthesis instead of the commonly performed iliosacral screw osteosynthesis passing the SI-joint. Symphyseal platting is performed to reduce and stabilize the anterior ring if necessary.

Main outcome measurements

Data were analyzed as follows: pelvic fracture classification; functional outcome; radiographic outcome; Leg length discrapency; and CT scan aspect of the sacroiliac joint.

Results

Associated pelvic injuries were present in all the patients and include symphysis rupture and acetabular fractures. Four of the seven patients had fractures of the lower extremities. Follow-up was available for all patients at an average of 27 months (range, 32–24 months). Neither septic nor cutaneous complications were reported. No loss of post-op reduction and no fixation failure were observed. The functional results noted at the last examination were satisfactory with a mean Majeed score of 93.

Conclusion

In our opinion, this surgical technique may be indicated in Tile type C1.2 (61C3-2 OTA class) pelvic ring disruption. It obviously reaches its limits in sacral fractures. The technique described provides effective control of vertical displacement while providing a certain degree of horizontal mobility to facilitate reduction and osteosynthesis of anterior lesions. The quality of the fixation allowed early weight bearing.     

Is there a role for percutaneous pelvic and acetabular reconstruction?

The primary goal in the treatment of pelvic fractures is the restoration of haemodynamic stability. The secondary goal is the reconstruction of stability and symmetry of the pelvic ring. Percutaneous reconstruction can only be accepted if these goals are met. The type of definitive surgery is dependent of the degree of instability of the anterior and posterior pelvic ring. Retrograde transpubic screw fixation of pubic rami fractures is a good alternative to external fixation or plate and screw osteosynthesis. The technique of screw placement and image intensifier control is explained. Internal fixation of pure sacroiliac dislocations, fracture-dislocations of the sacroiliac joint and sacral fractures can be fixed with sacroiliac screws, placed percutaneously. Reduction of the fracture or dislocation is performed closed, or open if anatomy cannot be restored in a closed manner. The primary goal in the treatment of acetabular fractures is to restore anatomy. Reduction comes before fixation. The goal of minimising approaches cannot be more important. In most cases open reduction will be necessary to achieve anatomical reconstruction. Only the experienced acetabular surgeon will be able to decide when and how he can restore anatomy through a less invasive approach or with a percutaneous procedure. The anterior column screw can be inserted through a separate incision in addition to a Kocher-Langenbeck approach. It is the same screw as the retrograde transpubic screw but placed in the opposite direction. The posterior column screw is placed percutaneously from the lateral cortex of the ilium in the direction of the posterior column. Techniques of placement of both screws are demonstrated. Open reduction and internal fixation remains the standard of care in stabilisation of pelvic and acetabular fractures. Only the experienced surgeon will be able to judge if percutaneous procedures can be an alternative or a useful additive to conventional techniques.     

S1 pediculoiliac screw fixation in instabilities of the sacroiliac complex: biomechanical study and report of two cases

OBJECTIVE: A new technique for posterior sacroiliac fixation is described and compared with conventional techniques. PATIENTS/MATERIAL AND METHODS: A patient with sacral alar fracture (zone 1) and another one with sacroiliac joint instability due to tuberculous infection underwent fixation using screws placed in the S1 pedicle and the iliac bone. Vertical stability of the new technique also was investigated using polyurethane pelvic bone analogs and compared with anterior double plating (group P) and iliosacral screw fixation (group ISS) techniques. RESULTS: Healing was obtained and reduction was maintained in both patients on the final follow-up examination at 2 years postoperatively. Vertical loading tests revealed that failure loads within the first 10 mm of displacement of the new pediculoiliac screw fixation technique (group PIS) was higher than plating (P = 0.03) and lower than ISS techniques (P = 0.002). Ultimate failure load of the PIS technique was slightly higher than plating (P = 0.277) and lower than ISS techniques (P = 0.003). With the addition of an iliosacral screw to the pediculoiliac screw construction (PIS+ISS), the PIS technique became more stable in early (P = 0.110) and ultimate failure loads (P = 0.003). CONCLUSIONS: Pediculoiliac screw fixation for sacroiliac joint disruptions and zone I sacrum fractures using iliac and S1 pedicle screws is a new and effective alternative for obtaining and maintaining anatomic reduction.     

Comparison of the risk of breakage of two kinds of sacroiliac screws in the treatment of bilateral sacral fractures

Purpose

This study aimed at comparing the risk of breakage of lengthened sacroiliac screw and ordinary sacroiliac screw for the treatment of bilateral vertical sacral fractures to provide reference for clinical application.

Methods

A finite element model of type C pelvic ring injury (bilateral type Denis II fracture of sacrum) was produced. The bilateral sacral fractures were fixed with lengthened sacroiliac screw and ordinary sacroiliac screw in seven types of models, respectively. The maximal Von Mises stresses and stress distribution of the two kinds of screws in the case of standing on both feet were measured and compared.

Results

(1) Whether in lengthened sacroiliac screw or ordinary sacroiliac screw, the maximal Von Mises stress of screw fixation only in S1 segment is the largest, and the maximal Von Mises stress of screw fixation only in S2 segment is minor, and the maximal Von Mises stress of screw fixation in S1 and S2 segments, respectively, is the least. (2) When S1 and S2 were both fixed with ordinary screws, the maximal Von Mises stress of screw in S1 segment is larger than that of S2. When S1 and S2 were both fixed with lengthened screws, the maximal Von Mises stress of screw in S1 segment is similar to that of S2. (3) The maximal Von Mises stresses of bilateral symmetrical screws are similar. (4) When only S1 was fixed, the maximal Von Mises stress of lengthened screw is less than that of ordinary screw. When only S2 was fixed, the maximal Von Mises stress of lengthened screw is larger than that of ordinary screw. When S1 and S2 were both fixed, the maximal Von Mises stress of lengthened screw is slightly less than that of ordinary screw. (5) Whether in lengthened screw or ordinary screw, the stress concentrations all exhibited at the regions of screws corresponding to the sacral fracture regions and the part between sacral bilateral fracture lines. Compared with ordinary screw, the stress distribution in lengthened screw is more homogeneous. Whether in lengthened screw or ordinary screw, the stress distribution of only one sacral segment fixation is more concentrated than that of two sacral segments’ fixation. When S1 and S2 were both fixed, the stress distribution of upper screw is more concentrated and that of lower screw is more homogeneous.

Conclusion

In a finite elements simulated type C pelvic ring disruption (bilateral type Denis II sacral fracture), the breakage risk of screws fixed in double-segment bilaterally symmetrically is low, and the breakage risk of screws fixed in S2 segment is lower than that of S1 segment. The bilaterally symmetrical screw fixation in double-segment is strongly recommended to reduce the breakage risk of screws. In addition, the breakage risk of lengthened screws is lower than that of ordinary screws except when screws are fixed in only S2 segment, which merits attention.     

仰卧位经皮骶髂置钉固定术治疗骨盆后环损伤

目的 探讨仰卧位经皮骶髂置钉固定术治疗骨盆后环损伤的可行性、手术方法及疗效.方法 在10具尸体操作的基础上,2004年10月至2007年10月对14例骨盆后环损伤行仰卧位经皮骶髂置钉固定术.男7例,女7例;年龄28～75岁,平均41.6岁.Tile B型损伤4例,C型损伤10例.患者仰卧位,于"C"型臂X线机透视下以髂前上棘上2 cm与腋后线交点及髂前上棘与髂后上棘连线中、后1/3交点为进钉点,若两点距离较大,则在透视下确定最佳进钉点.进钉角度为向前20°～30°角,向尾端倾斜5°～15°.经皮骶髂置入一枚直径7.2 mm空心钛螺钉固定.术后摄骨盆正位、骶骨侧位X线片,并行骶髂关节CT扫描,观察螺钉在S1椎体的位置.结果 14例均获随访,平均随访16个月.术后3个月骨盆骨折均临床愈合.14例共置入15枚空心钛螺钉,未发生与置钉有关的并发症.随访期间无神经损伤、螺钉松动及断裂现象,无骨盆畸形及骶髂部疼痛.Majeed疗效评定标准优良率为92.9%.结论 采用体表双定位法,可提高仰卧位骶髂置钉固定术的安全性;仰卧位经皮骶髂置钉固定术治疗骨盆后环损伤方便、可行.     

选择性增加伤椎单侧置钉内固定治疗胸腰段椎体骨折

目的探讨选择性增加经伤椎椎弓根置钉短节段钉棒内固定治疗胸腰段椎体骨折的临床效果。方法选择22例胸腰段椎体骨折,采用增加经伤椎椎弓根置钉短节段钉棒内固定,观察患者术前、术后伤椎前缘高度、脊柱Cobb角、神经恢复情况。结果术后伤椎前缘高度、脊柱Cobb角较术前明显恢复(P<0.01),无断钉、断棒。结论选择性增加经伤椎椎弓根置钉短节段钉棒内固定治疗胸腰椎严重骨折,术中伤椎复位满意、术后固定牢固、脊柱稳定性好,有利于伤椎骨折愈合和患者早期功能锻炼与康复。     

Die perkutane transiliosakrale Zugschraubenosteosynthese des hinteren Beckenrings

BACKGROUND: In recent years, the closed reduction and percutaneous fixation of posterior pelvic ring fractures by sacroiliac screws has become a well established treatment option for stabilization of posterior pelvic ring disruptions. Stable percutaneous pelvic ring fixation also implies a very low complication rate, e.g., in operative blood loss, wound healing, and operative time. To avoid malpositioning of the screws, sufficient reduction and radiologic visualization are essential. The surgical technique has been described in several studies; however, great importance is attached to the personal experience of the surgeon. Therefore, this study was conducted to establish a standard procedure that allows different surgeons a safe positioning of sacroiliac screws. RESULTS: A total of 41 injuries of the posterior pelvic ring were stabilized with 73 sacroiliac lag screws inserted by 7 different surgeons using a standardized technique. In all cases adequate reduction of the fracture and radiologic visualization were achieved. No wound infections, no relevant bleedings, and no spiral fractures of screws were observed. In two cases malpositioning led to revision of the screws. Of interest, one case of S1 paresthesia resulting from a malpositioned screw could be revised. In contrast, two cases of screw loosening and one case of screw bending did not require further intervention. CONCLUSION: We conclude that safe positioning of the sacroiliac screws was accomplished by all surgeons given a standardized technique. For safe insertion preparation of the patients, accurate visualization of the fracture zone, and potential closed reduction is always required.     

Osseointegrated wrist-joint prostheses: a 15-year follow-up with focus on bony fixation.

Five patients with rheumatoid arthritis or osteoarthrosis of the wrist joint were followed up for 15 (14-17) years after wrist-joint arthroplasty with semiconstrained artificial joint mechanisms that had been anchored to bone using the osseointegration principle. They were fixed by one titanium screw introduced into the radius, and two or more titanium screws introduced distally into the metacarpal bones. In four cases a screw was also introduced into the ulna thereby constituting one component in a distal radio-ulnar (DRU) joint mechanism. The titanium screw introduced into the radius and the distal metacarpal screws osseointegrated in all cases. In three cases the mechanism of the wrist joint or parts of it were replaced with new components that could be attached to the screws that were already osseointegrated. We conclude that wrist joint prostheses can be anchored to the surrounding bone using osseointegration and that they remain fixed for at least 15 years. The principle allows replacement of the joint mechanism, if needed, with maintenance of the osseointegrated anchoring elements.     

Modified lumbopelvic fixation for sacral and L5 fractures associated with spinopelvic instability: a case report and introduction of the surgical technique

Posterior lumbopelvic fixation with iliac screws is the most commonly used method for unstable spinopelvic injuries. It has certain limitations including inability to use distraction along the spinopelvic rod as an indirect reduction maneuver, need for complex 3-dimensional rod contouring and complications such as hardware prominence and soft tissue coverage. In the present case report,we described a surgical technique of lumbopelvic fixation with sacral alar screws for traumatic spinopelvic instability resulted from a unilateral Denis-Ⅲ comminuted sacral fracture and the L5 burst fracture. On the opposite side of the sacral fracture, caudal screws were implanted into the pedicle of the S1, whereas on the side of sacral fracture, two sacral alar screws were placed parallel to the superior sacral endplate as well as the plane of sacroiliac joint. In addition,horizontal stabilization was conducted with cross-link connections to maintain the longitudinal traction. For sacral fracture associated with traumatic spinopelvic instability,this modified lumbopelvic fixation technique using sacral alar screws makes longitudinal reduction easier, requires less rod contouring, and reduces hardware prominence without compromising the stability.     

The invention of an iliosacral screw fixation guide and its preliminary clinical application

Objective: To introduce an iliosacral screw fixation guide and evaluate its efficacy in fixation of sacroiliac joint fracture‐dislocations. Methods: Between January 2011 and May 2011, eight patients (five men, three women) with sacroiliac joint fracture‐dislocation underwent percutaneous iliosacral screw fixation with the assistance of this minimally invasive guide and under CT guidance. The patients, aged from 26 to 56 years (mean 32 years), had vertically unstable pelvic fractures. Before surgery, six patients who had displacement of >2 cm in their sacroiliac joints underwent skeletal traction on the femoral condyle. The inserted sites were marked out on the affected side of their buttocks after the best screw trajectory had been determined under CT control. The gear that controls the direction of the minimally invasive guide was adjusted according to the inserting angle determined by CT scans. A K‐wire was inserted into the sacroiliac joint along the pilot sleeve of the guide, and a hollow screw (diameter 7.3 mm) was implanted into the sacroiliac joint along the K‐wire. Results: All eight operations were successful on the first attempt. The operations lasted from 10 to 20 minutes (mean 14 minutes). Immediate CT scans confirmed that all the screws had been placed in the desired positions, none had penetrated the bones and the configuration of the sacroiliac joints had been satisfactorily restored and firmly fixed. No patient experienced numbness or radiating pain in the lower limbs during surgery. There were no postoperative vascular or neurological complications. Conclusion: The minimally invasive guide can eliminate discrepancies resulting from the surgeon's own sensory input when inserting screws under the guidance of CT, making percutaneous iliosacral screw fixation more accurate, safe and simple.     

Augmentation of occipitocervical contoured rod fixation with C1-C2 transarticular screws.

BACKGROUND CONTEXT: The technique of occipitocervical fusion using a threaded contoured rod attached with sublaminar wires to the occiput and upper cervical vertebrae is widely used throughout the world and has been clinically proven to provide effective fixation of the destabilized spine. However, this system has some disadvantages in maintaining stability, especially at C1-C2 because of the large amount of axial rotation at this level. In some clinical situations such as fracture of the C1 lamina, C1 laminectomy, and excessively lordotic curvature, it is not always possible to wire C1 directly into the construct. In such cases, combination of other stabilization methods that include C1 indirectly can be used to achieve a reliable posterior internal fixation. PURPOSE: Primarily, to evaluate whether a contoured rod construct in which C1 is indirectly included using C1-C2 transarticular screws is biomechanically equivalent to a standard, fully wired contoured rod construct. Secondarily, to evaluate the biomechanical benefit of adding C1-C2 transarticular screws to a fully wired contoured rod construct. STUDY DESIGN: Repeated-measures nondestructive in vitro biomechanical testing of destabilized cadaveric human occipitocervical spine specimens. METHODS: Six human cadaveric specimens from the occiput to C3 were studied. Angular and linear displacement data were recorded while nonconstraining nondestructive loads were applied. Three methods of fixation were tested: contoured rod incorporating C1 with and without transarticular screws and contoured rod with transarticular screws without incorporating C1. RESULTS: All three constructs reduced motion to well within normal range. In contoured rod constructs with C1 wired, addition of transarticular screws slightly but significantly improved stability. In constructs with transarticular screws, incorporation of C1 into the contoured rod wiring did not improve stability significantly. CONCLUSIONS: Adding C1-C2 transarticular screws to a wired contoured rod construct where C1 is included only slightly improves stability. As the absolute reduction in motion from adding transarticular screws is small (<1 degree), it is doubtful whether any enhanced fusion from this additional procedure outweighs the surgical risks. However, transarticular screws provide an effective alternate method to fixate C1 when the posterior arch of C1 is absent or has been fractured.     

Sacroiliac fixation: a new technique after pelvic trauma

We propose a new technique for sacroiliac fixation for the treatment of pelvic fracture with vertical and horizontal instability (Tile class C). This fixation technique allows control of vertical displacement while allowing, if needed, a certain degree of movement in the horizontal plane to facilitate reduction of anterior lesions. The technique involves insertion of two sacral screws, one in S1 and one in S2, and two iliac screws. The iliac screws are inserted in the posterior iliac crest through two sacroiliac connectors placed on a rod linking the two sacral screws. Vertical displacement is controlled by blocking the screw heads on the connecting rod. If needed, a certain degree of horizontal mobility of the half pelvis can be allowed by loosening the connectors on the rods. This technique was used for 4 patients. Anatomic reduction was achieved and no secondary movement of the osteosynthesis material nor secondary displacement were observed. The quality of the fixation allowed rapid weight bearing in the standing position and early walking without crutches. This type of fixation can only be used for type C12 fractures in the Tile classification.     

Biomechanical comparison of posterior pelvic ring fixation

OBJECTIVE: To determine relative stiffness of various methods of posterior pelvic ring internal fixation. DESIGN: Simulated single leg stance loading of OTA 61-Cl.2, a2 fracture model (unilateral sacroiliac joint disruption and pubic symphysis diastasis). SETTING: Orthopaedic biomechanic laboratory. OUTCOME VARIABLES: Pubic symphysis gapping, sacroiliac joint gapping, hemipelvis coronal plane rotation. METHODS: Nine different posterior pelvic ring fixation methods were tested on each of six hard plastic pelvic models. Pubic symphysis was plated. The pelvic ring was loaded to 1000N. RESULTS: All data were normalized to values obtained with posterior fixation with a single iliosacral screw. The types of fixation could be grouped into three categories based on relative stiffness of fixation: For sacroiliac joint gapping, group 1-fixation stiffness 0.8 and above (least stiff) includes a single iliosacral screw (conditions A and J), an isolated tension band plate (condition F), and two sacral bars (condition H); group 2-fixation stiffness 0.6 to 0.8 (intermediate stiffness) includes a tension band plate and an iliosacral screw (condition E), one or two sacral bars in combination with an iliosacral screw (conditions G and I); group 3-fixation stiffness 0.6 and below (greatest stiffness) includes two anterior sacroiliac plates (condition D), two iliosacral screws (condition B), and two anterior sacroiliac plates and an iliosacral screw (condition C). For sacroiliac joint rotation, group 1-fixation stiffness 0.8 and above includes a single iliosacral screw (conditions A and J), two anterior sacroiliac plates (condition D), a tension band plate in isolation or in combination with an iliosacral screw (conditions E and F), and two sacral bars (condition H); group 2-fixation stiffness 0.6 to 0.8 (intermediate level of instability) includes either one or two sacral bars in combination with an iliosacral screw (conditions G and I); group 3-fixation stiffness 0.6 and below (stiffest fixation) consists of two iliosacral screws (condition B) and two anterior sacroiliac plates and an iliosacral screw (condition C). DISCUSSION: Under conditions of maximal instability with similar material properties between specimens, differences in stiffness of posterior pelvic ring fixation can be demonstrated. The choice of which method to use is multifactorial.     

骶髂关节空心钉内固定导向器的研制及临床应用

目的 自行设计并研制一种骶骼关节空心钉内固定导向器,以期提高S1椎弓根空心钉置入的成功率及置入质量。方法 自行设计并研制的骶髂关节空心钉内固定导向器由带有测量长度的定位器、带有角度刻度表的水平面S1椎弓根空心钉置入角（TSA）、矢状面置入角(SSA)调节器及固定螺丝等组成。2006年6月至2009年10月共收治15例不稳定型骨盆骨折累及骶髂关节者,男6例,女9例;年龄19 ～ 60岁,平均45.6岁。不稳定型骨盆骨折经骶髂关节韧带3例,经骶骨Ⅰ区5例,累及骶骨Ⅱ区5例,累及骶骨Ⅲ区2例。15例患者均采用骶髂关节空心钉内固定导向器引导术中空心钉的操作,共置入18枚空心钉。结果 术后CT及X线片示18枚空心钉置入位置准确,与术前设计相比,具有相同或相近的TSA及SSA。结论 骶骼关节空心钉内固定导向器设计合理,使用方便,能提高S1椎弓根空心钉置入的准确性及置入质量,且可显著减少C型臂X线机的透视次数。     

Posterior C1-C2 fusion with polyaxial screw and rod fixation.

STUDY DESIGN: A novel technique of atlantoaxial stabilization using individual fixation of the C1 lateral mass and the C2 pedicle with minipolyaxial screws and rods is described. In addition, the initial results of this technique on 37 patients are described. OBJECTIVES: To describe the technique and the initial clinical and radiographic results for posterior C1-C2 fixation with a new implant system. SUMMARY OF BACKGROUND DATA: Stabilization of the atlantoaxial complex is a challenging procedure because of the unique anatomy of this region. Fixation by transarticular screws combined with posterior wiring and structural bone grafting leads to excellent fusion rates. The technique is technically demanding and has a potential risk of injury to the vertebral artery. In addition, this procedure cannot be used in the presence of fixed subluxation of C1 on C2 and in the case of an aberrant path of the vertebral artery. To address these limitations, a new technique of C1-C2 fixation has been developed: bilateral insertion of polyaxial-head screws in the lateral mass of C1 and through the pars interarticularis into the pedicle of C2, followed by a fluoroscopically controlled reduction maneuver and rod fixation. METHODS: After posterior exposure of the C1-C2 complex, the 3.5-mm polyaxial screws are inserted in the lateral masses of C1. Two polyaxial screws are then inserted into the pars interarticularis of C2. Drilling is guided by anatomic landmarks and fluoroscopy. If necessary, reduction of C1 onto C2 can be accomplished by manipulation of the implants, followed by fixation to the 3-mm rod. For definitive fusion, cancellous bone can be added. No structural bone graft or wiring is required. In selected cases, e.g., C1-C2 subluxation or fractures in young patients in whom only temporary fixation is necessary, the instrumentation can be removed after an appropriate time. Because the joint surfaces stay intact, the patient can regain motion in the C1-C2 joints. RESULTS: Thirty-seven patients underwent this procedure. No neural or vascular damage related to this technique has been observed. The early clinical and radiologic follow-up data indicate solid fusion in all patients. CONCLUSION: Fixation of the atlantoaxial complex using polyaxial-head screws and rods seems to be a reliable technique and should be considered an efficient alternative to the previously reported techniques.