Aims. We compared the accuracy, operating time and radiation exposure of the introduction of iliosacral screws using O-arm/Stealth Navigation and standard fluoroscopy. Materials and Methods. Iliosacral screws were introduced percutaneously into the first sacral body (S1) of ten human cadavers, four men and six women. The mean age was 77 years (58 to 85). Screws were introduced using a standard technique into the left side of S1 using C-Arm fluoroscopy and then into the right side using O-Arm/Stealth Navigation. The radiation was measured on the surgeon by dosimeters placed under a lead thyroid shield and apron, on a finger, a hat and on the cadavers. Results. There were no neuroforaminal breaches in either group. The set-up time for the O-Arm was significantly longer than for the C-Arm, while total time for placement of the screws was significantly shorter for the O-Arm than for the C-Arm (p = 0.001). The mean absorbed radiation dose during fluoroscopy was 1063 mRad (432.5 mRad to 4150 mRad). No radiation was detected on the surgeon during fluoroscopy, or when he left the room during the use of the O-Arm. The mean radiation detected on the cadavers was significantly higher in the O-Arm group (2710 mRem standard deviation (. sd. ) 1922) than during fluoroscopy (11.9 mRem . sd 14.8). (p < 0.01). Conclusion. O-Arm/Stealth Navigation allows for faster percutaneous placement of iliosacral screws in a radiation-free environment for surgeons, albeit with the same accuracy and significantly more radiation exposure to cadavers, when compared with standard fluoroscopy. Take home message: Placement of iliosacral screws with O-Arm/Stealth Navigation can be performed safely and effectively. Cite this article: Bone Joint J 2016;98-B:696–702

Purpose. To evaluate the use of cutaneous marking of the sacrum for percutaneous iliosacral screw fixation. Iliosacral screw placement is dependent upon spatial perception, multiplanar fluoroscopic imaging, and an appreciation of pelvic anatomy which often makes learning the technique difficult for residents. Cutaneous marking of the sacrum may facilitate iliosacral screw insertion by providing additional cues to the orientation of the sacrum. Method. A cross-over study design was used for placing iliosacral screws in whole cadaver specimens using standardized operative and imaging techniques with and without cutaneous sacral markings. Lateral fluoroscopic imaging and a radio-opaque straight edge were used to trace the lateral profile of the sacrum with a marking pen. Total procedure time and fluoroscopy time were recorded. A total of 14 residents (6 seniors and 8 juniors) each placed two iliosacral screw guide-wires in a total of seven whole cadavers (14 SI joints). Group 1 performed the procedure first with no markings and then with markings. Group 2 performed the procedure first with markings and then without markings. Statistical analysis included T test, Wilcoxon Rank Sum Test, and Signed-Rank Test for Difference (p = 0.05). Participants also reported their opinions on each technique. Results. Mean procedure time for Group 1 was 8.83 minutes (3.77 17.17) and mean fluoroscopy time was 0.77 minutes (0.4 1.2) for the no-marking attempt and 10.33 min (5.88 15.25) and 1.06 min (0.6 2.3) respectively for the marking attempt. Mean procedure time for Group 2 was 11.3 min (6.33 16.5) and mean fluoroscopy time was 1.19 min (0.6 2.3) for the marking attempt and 7.22 min (2.83 17.27) and 0.97 min (0.4 1.8) respectively for the no-marking attempt. There were no significant differences between groups. T test analysis of all marking vs. no marking showed no significant difference for total procedure time (p= O.7020) or fluoroscopy time (p= 0.8297). Wilcoxon Rank Sum Test analysis showed no significant difference for total procedure time (p= 0.4415) or fluoroscopy time (p=0.7486) and Signed-Rank Test for Difference showed no significant difference for total procedure time (p=0.0625) or fluoroscopy time (p=0.1459). Senior residents reported they found the cutaneous marking helpful and would use it again whereas junior residents had mixed feelings on its utility. Conclusion. Cutaneous marking of the sacrum did not significantly impact total procedure time or fluoroscopy time but was generally reported to be helpful for residents learning percutaneous iliosacral screw fixation

Objectives. Percutaneous iliosacral screw placement is a standard, stabilization technique for pelvic fractures. The purpose of this study was to assess the effectiveness of a novel biplanar robot navigation aiming system for percutaneous iliosacral screw placement in a human cadaver model. Methods. A novel biplanar robot navigation aiming system was used in 16 intact human cadaveric pelvises for percutaneous iliosacral screw insertion. The number of successful screw placements and mean time for this insertion and intra-operative fluoroscopy per screw-pair were recorded respectively to evaluate the procedure. The accuracy of the aiming process was evaluated by computed tomography. Results. Sixteen intact human cadaveric pelvises were treated with percutaneous bilateral iliosacral S1 screw placement (32 cannulated screws, diameter-7.3mm, Synthes, Switzerland). All screws were placed under fluoroscopy-guided control using the biplanar robot navigation aiming system (TINAV, GD2000, China). There was no failed targeting for screw-pair placements. Computed tomography revealed high accuracy of the insertion process. 32 iliosacral screws were inserted (mean operation time per screw-pair 56 ± 3 minutes, mean fluoroscopy time per screw-pair 11.7 ± 9 seconds). In post-operative CT-scans the screw position was assessed and graded as follows: I. secure positioning, completely inserted in the cancellous bone (86%); II. secure positioning, but contacting cortical bone structures (9%); III. malplaced positioning, penetrating the cortical bone (5%). Conclusion. This cadaver study indicated that an aiming device–based biplanar robot navigation system is highly reliable and accurate. The promising results suggest that it has the advantages of high positioning accuracy, decreased radiation exposure, operational stability and safety. It can be used not only for the percutaneous iliosacral screw placement but also for other orthopedic surgeries that require precise positioning

There has been a trend towards operative management of pelvic injuries. Posterior pelvic integrity is more important for functional recovery. Percutaneous iliosacral screw fixation is being increasingly preferred for posterior pelvic stabilisation. Outcome reporting for this procedure remains inconsistent and un-standardised. Retrospectively, all percutaneous iliosacral screw fixations done at this institute during a 5-year period (2008–2012) were reviewed. 28 patients, who had had at least 12 months follow-up, were contacted and clinical scoring was done by postal correspondence. Radiographs were measured for displacements and leg-length discrepancy. Possible factorial associations and correlations were investigated. Mean Majeed score was 83 (median 87), mean EQ-Visual Analog Score (EQ-VAS) was 75.5 (median 80) and the two scores were correlated with statistical significance. Tile AO type C injuries produced worse outcomes and patients who'd anterior pelvic fixation did better. Our results show high patient-reported outcomes, excellent radiologically measured reductions and unions. The incidence of complications is very low. There is a significant correlation between the EQ-VAS arm of the EQ5D instrument and the Majeed score in this patient population. Incidence of non-pelvic surgical procedures in these patients was significantly associated with worse outcomes. Leg length discrepancies appeared to increase after patients were fully weight bearing

We hypothesised that the anterior and posterior walls of the body of the first sacral vertebra could be visualised with two different angles of inlet view, owing to the conical shape of the sacrum. Six dry male cadavers with complete pelvic rings and eight dry sacrums with K-wires were used to study the effect of canting (angling the C-arm) the fluoroscope towards the head in 5° increments from 10° to 55°. Fluoroscopic images were taken in each position. Anterior and posterior angles of inclination were measured between the upper sacrum and the vertical line on the lateral view. Three authors separately selected the clearest image for overlapping anterior cortices and the upper sacral canal in the cadaveric models. The dry bone and K-wire models were scored by the authors, being sure to check whether the K-wire was in or out. In the dry bone models the mean score of the relevant inlet position of the anterior or posterior inclination was 8.875 (standard deviation (. sd. ) 0.35), compared with the inlet position of the opposite inclination of –5.75 (. sd. 4.59). We found that two different inlet views should be used separately to evaluate the borders of the body of the sacrum using anterior and posterior inclination angles of the sacrum, during placement of iliosacral screws. Cite this article: Bone Joint J 2015;97-B:705–10

Introduction We present prospective and retrospective reviews of sacral nonunions treated with posterior tension band plate and iliosacral screws at Frenchay Hospital from 1994. Methods Using the pelvis data base at Frenchay (Bristol, UK) Hospital six patients were identified. A further two patients were followed prospectively. Clinical outcome was measured using a visual analogue score ( VAS ) for pain. Radiological analysis was done using pre-injury x-ray and CT when available, pre-revision and post-operative CT. Eight patients were reviewed. Average follow-up was two years (range 6 months to 5.5 years). The average time from initial injury and surgery to diagnosis of sacral nonunion was 7.5 months (range 3 to 18). Six patients had been treated previously with sacro-iliac screws and an anterior external fixator. Results Pre-operative VAS scores averaged 9.2, postoperatively they averaged 3.4. All nonunions fused radiologically post-operatively. Anterior posterior displacement was able to be corrected by an average of five millimetres. The three fractures that were vertically displaced were not corrected because of coexisting neurological injury. Conclusions Posterior tension band plating and iliosacral screw fixation reliably allows union to be obtained in sacral nonunions

Minimally invasive placement of iliosacral screws (SI-screw) is becoming the standard surgical procedure for sacrum fractures. Computer navigation seems to increase screw accuracy and reduce intraoperative radiation compared to conventional radiographic placement. In 2012 an interdisciplinary hybrid operating theatre was installed at the University of Ulm. A floor-based robotic flat panel 3D c-arm (Artis zeego, Siemens, Germany) is linked to a navigation system (BrainLab Curve, BrainLab, Germany). With a single intraoperative 3D scan the whole pelvis can be visualised in CT-like quality. The aim of this study was to analyse the accuracy of SI-screws using this hybrid operating theater. 32 SI-screws (30 patients) were included in this study. Indications ranged from bone tumour resection with consecutive stabilisation to pelvic ring fractures. All screws were implanted using the hybrid operating theatre at the University of Ulm. We analysed the intraoperative 3D scan or postoperative computed tomography and classified the grade of perforation of the screws in the neural foramina and the grade of deviation of the screws to the cranial S1 endplate according to Smith et al. Grade 0 stands for no perforation and a deviation of less than 5 °. Grade 1 implies a perforation of less than 2 mm and a deviation of 5–10°, grade 2 a perforation of 2–4 mm and a deviation of 10–15° and grade 3 a perforation of more than 4 mm and a deviation of more than 15°. All patients were tested for intra- and postoperative neurologic complications and infections. The statistical analysis was executed using Microsoft Excel 2010. 32 SI-screws were implanted in the first 20 months after the hybrid operating theatre had been established in 2012. All 30 patients were included in this study (15 men, 15 women). The mean age was 59 years ±23 (13–95 years). 20 patients received a single screw in S1 (66.7%), 1 patient 2 unilateral screws in S1 and S2 (3.3%), one patient 2 bilateral screws in S1 (3.3%) and 8 patients a single screw stabilising both SI-joints (26.7%). 27 screws showed no perforation (84.4%), 1 screw a grade 1 perforation (3.1%) and 4 screws a grade 2 perforation (12.5%). There was no grade 3 perforation. Furthermore there was no perforation of the neural foramina or the ventral cortex in the axial plane of the SI-screws stabilising one SI-joint (24 screws). Only single SI-screws bridging both SI joints showed a perforation of the neural foramina (37% grade 0, 12.5% grade 1, 50% grade 2, 0% grade 3). In the frontal plane 23 screws (71.9%) showed a deviation of less than 5°. In 5 screws a grade 1 deviation (15.6%) and in 4 screws a grade 2 deviation (12.5%) could be found. There was no grade 3 deviation. There were no infections or neurological complications. The high image quality and large field of view in combination with an advanced navigation system is a great benefit for the surgeon. All SI-screws stabilising only one joint showed completely intraosseous placement. Single SI-screws bridging 2 SI-joints intentionally perforated the neural foramina ventrally in 5 cases because of dysmorphic sacral anatomy. This makes image-guided implantation of SI-screws in a hybrid operating theatre a very safe procedure

Various techniques have been used for the fixation of the posterior pelvis, each with disadvantages specific to the technique. In this study, a new protocol involving the placement of posterior pelvic screws in the CT suite is described and evaluated. A total of 66 patients with unstable pelvic ring injuries was stabilised under local anaesthesia with sedation. The mean length of time for the procedure was 26 minutes per screw. There were no technical difficulties or misplaced screws and no cases of infection or nonunion. All patients stated that they would choose to have the CT scan procedure again rather than a procedure requiring general anaesthesia. The charges for the procedure were approximately £1840 ($2800) per operation. CT-guided placement of iliosacral screws is a safe, feasible, and cost-effective alternative to radiologically-guided placement in the operating theatre in selected patients

Introduction: Percutaneous iliosacral screws are commonly used for the fixation of the posterior pelvis. The procedure is technically demanding because of the limitations of radiological visualisation of the relevant landmarks. There have been several reports of misplaced screws and other complications, occasionally with serious consequences. To achieve a secure surgical procedure we routinely use a CT-guided technique for percutaneous pelvic screw fixation since 2004. Methods: Between September 2004 and January 2009, 39 patients were treated using CT-guided screw fixation. Under general anaesthesia patients were placed on a vacuum mattress in a stable lateral position within the CT gantry (Siemens SOMATOM definition; i-Fluoro: 20mAs; Hand CARE mode). The scanner bed was on a calibrated track so the same images could be used and repeated throughout the procedure. Gantry and patient were draped under sterile conditions. The laser sights of the CT indicated the cutaneous site which corresponded to the underlying osseous level (first or second sacral pedicle). At this the CT scan trajectory in the CT-fluoro mode indicated the extrapolated position of the guide-wire. A 3.2mm guide-wire was inserted using battery-powered equipment or hammer blows. When the guide-wire was in a correct position a self-drilling cannulated lag screw was placed (6.5mm DePuy). Two screws were inserted in sacral fractures, one screw in sacroiliac ligament ruptures. Results: 19 of 39 patients were polytraumatized. In 10 cases there were both side injures. Overall 71 screws were placed. Median time for the procedure was 36 minutes in unilateral lesions and 48 min in bilateral lesions. There were no cases of infection, non-union or neurological deficit. Postoperative CT revealed correct screw positions in all cases. Screw removal was done routinely in the patients younger than sixty years to resolve the blocked sacroiliac joint. Conclusions: CT-guided is a safe and feasible treatment option in patient with instable pelvic ring lesions. A close collaboration between interventional radiologist and surgeon is essential. Compared to other procedures g.e. internal plate fixation or fluoroscopic guided procedures CT-guided screw insertion seems to be more secure and could strongly be advocated

The royal victoria hospital is a tertiary trauma centre receiving pelvic injury referrals for a population of 1.7 million. The use of ilio-sacral screw fixation with low anterior frame stabilisation has been adopted as the principle treatment for unstable pelvic ring injuries in our institution. We aim to describe our practice and outcomes following the use of percutaneous screw fixation of the pelvis.

The review included standardised assessment of health-related quality of life (SF-36) as well as the Iowa pelvic score and Majeed pelvic injury outcome scores. Data was also collected on associated injuries, post-operative complications, nerve injury and pain scores.

A total case series of 45 patients undergoing percutaneous ilio-sacral screw fixation following traumatic pelvic injury were identified over a 5 year period. Of these 23 were contactable to follow-up or responded to questionnaire review.

The mean follow up was 680 days (range 151–1962). The mean age was 33 (range 18–57).

The mean SF-36 physical and mental scores were 38 and 46 respectively. The mean Majeed score was 69 and Iowa pelvic score was 65. The mean pain score was 3.5 (range 0–7). There were no incidences of deep infection, post-operative PE or nerve injury related to screw insertion.

Patients with isolated pelvic injuries performed better on outcome scoring however the low SF-36 scores highlight the severity of pelvic injuries

Dysmorphic pelves are a known risk factor for malpositioned iliosacral screws. Improved understanding of pelvic morphology will minimise the risk of screw misplacement, neurovascular injuries and failed fixation. Existing classifications for sacral anatomy are complex and impractical for clinical use. We propose a CT-based classification using variations in pelvic anatomy to predict the availability of transosseous corridors across the sacrum. The classification aims to refine surgical planning which may reduce the risk of surgical complications. The authors postulated 4 types of pelves. The “superior most point of the sacroiliac joint” (sSIJ) typically corresponds with the mid-lower half of the L5 vertebral body. Hence, “the anterior cortex of L5” (L5. a. ) was divided to reference 3 distinct pelvic groups. A 4. th. group is required to represent pelves with a lumbosacral transitional vertebra. The proposed classification:. A – sSIJ is above the midpoint of L5. a. B – sSIJ is between the midpoint and the lowest point of L5. a. C – sSIJ is below the lowest point of L5. a. D – pelves with a lumbosacral transitional vertebra. Specific measures such as the width of the S1 and S2 axial and coronal corridors and the S1 lateral mass angles were used to differentiate between pelvic types. Three-hundred pelvic CT scans were classified into their respective types. Analysis of the specific measures mentioned above illustrated the significant difference between each pelvic type. Changes in the size of S1 and S2 axial corridors formed a pattern that was unique for each pelvic type. The intra- and inter-observer ratings were 0.97 and 0.95 respectively. Distinct relationships between the sizes of S1 and S2 axial corridors informed our recommendations on trans-sacral or iliosacral fixation, number and orientation of screws for each pelvic type. This classification utilises variations in the posterior pelvic ring to offer a planning guide for the insertion of iliosacral screws

Percutaneous fluoroscopically asseisted iliosacral screw insertion has become one of the most popular methods of stabilisation of the posterior aspect of the vertically unstable pelvis. Screw malpositioning rates range from 0 to 10%. Screw misplacement can cause injury to the iliac and gluteal vessels, L4 to s1 nerve roots and sympathetic chain. We performed two radiographic studies on dry human bones to seek safe radiographic landmarks for insertion of iliosacral screws. Part 1: Two parallel linear densities are always present on lateral plain radiographs of the lumbosacral spine and pelvis. Using wire markers on pelvic bones, we accurtely define the origins of these “pelvic lines”. Steel wires of different lengths were placed along the iliopectineal and arcuate lines of the pelvis. The shorter wire stopped at the anterior limit of the sacroiliac joint. The longer wire extended further along the entire course of the medial border of the ilium to the iliac crest posteriorly. We demonstrate that each “pelvic line” represents the sharp bony ridge that forms the anterosuperior limit for insertion of the iliosacral screws. Part 2: In a second experiment on dry pelvis, we inserted balloons filled with radio-opaque contrast medium into the spinal canal of the sacrum and exiting through the anterior and posterior sacral foramina on either side. Plain lateral radiographs and CT scan with reformatted images were obtained. We present a previously undescribed radiological sign on plain lateral radiographs of the lumbosacral spine. The inferior and posterior boundaries of the “acorn sign” are delineated. Together, the “pelvic lines” and “acorn sign” provide accurate landmarks for the safe insertion of iliosacral screws. Iliosacral screws should be contained within this “acorn sign” to avoid injury to the nerve roots and below the “pelvic lines” to safeguard the iliac vessels and lumbosacral trunk

Introduction and Aims: Surgical correction of pelvic obliquity is an important component of spinal instrumentation for neuromuscular scoliosis, though instrumentation to the pelvis has high reported complication rates. This study evaluates the results of pelvic fixation during surgical correction of neuromuscular scoliosis in a consecutive series of 62 children and adolescents. Method: A retrospective chart and radiographic review of 62 consecutive patients treated with spinal fusions to the pelvis as treatment for neuromuscular scoliosis was performed. Follow-up ranged from two to seven years. Diagnoses included cerebral palsy (36 patients), muscular dystrophy (16 patients), myelomeningocele (three patients), spinal muscular atrophy (three patients) and other disorders (four patients). Mean age at surgery was 13.5 years. Pelvic fixation techniques used included Luque-Galveston or iliosacral screw fixation. Correction of deformity in each patient was assessed with Cobb angle measurements of scoliosis, thoracic kyphosis, and lumbar lordosis. Pelvic obliquity and coronal decompensation was also assessed. Results: The Luque-Galveston spinal instrumentation technique was used in 54 patients and iliosacral screw fixation was used in eight patients. Seventeen patients had an additional anterior release and fusion without instrumentation. The mean Cobb angle measured 73 degrees pre-operatively and 31 degrees (mean correction 59%) post-operatively. The mean Cobb angle on latest follow-up was 33 degrees (loss of correction 12%). Thoracic kyphosis remained essentially unchanged, as did lumbar lordosis (56 pre-op and 61 on follow-up). Pelvic obliquity corrected from a mean of 16 degrees pre-operatively to eight degrees on most recent follow-up. Mean pre-operative coronal decompensation measured 135mm, and follow-up decompensation measured 46mm. Eleven patients with Galveston fixation exhibited the ‘windshield-wiper’ sign, with a radiolucency of 2mm or more, though most were asymptomatic. Wound infection was observed in 6% (3/54) of the patients who underwent Galveston instrumentation and 50% (4/8) who had iliosacral screws. In patients treated with Galveston fixation, three had symptomatic prominant hardware and one had hardware breakage for an overall mechanical failure rate of 7% (4/54). In contrast, two patients with iliosacral screws had construct breakage and pseudoarthrosis for a mechanical failure rate of 25% (2/8), though the numbers in the iliosacral screw group are small. Conclusions: In this series, Galveston pelvic fixation during spinal instrumentation treatment of neuromuscular scoliosis was associated with satisfactory results and with less complications than generally reported in the literature. This technique is recommended as the preferred method for pelvic fixation in severe neuromuscular scoliosis associated with pelvic obliquity

INTRODUCTION. Isolated injuries of the sacral bone are rare. The pathomechanism of these injuries are usually high velocity accidents or falls from large heights. The computer-assisted implantation of iliosacral screws (SI-screw) becomes more important in the treatment of dorsal pelvic ring fractures. The advantage of the minimal-invasive screw placement is the reduction of the non-union and deep wound infection rate. Another advantage of computer-navigated SI-screw placement is the reduction of intraoperative radiation for the patient and the surgical staff. The purpose of this study was to analyse the position of navigated iliosacral screws. METHODS. In the study group 74 screws (49 patients) were included and radiologically analysed. All screws were implanted using 3D-navigation (BrainLAB Vector Vision, Brainlab, Germany). Navigation was always executed with the same 3D c-arm (ARCADIS Orbic 3D, Siemens, Germany) and navigation system. We determined the grade of perforation and angular deviation in the postoperative CT-scans in all screws. The classification was performed according to Smith et al in 4 grades. Grade 0 implies no perforation and grade 1 a perforation less than 2 mm. Grade 2 correlates a perforation of 2–4 mm and grade 3 a perforation of more than 4 mm. Furthermore the intra- and postoperative complications as well as the body-mass-index, the co-morbidities and the duration of radiation were documented. The statistical analysis was executed using Microsoft Excel 2003. RESULTS. The mean age of the 49 patients was 42.2 years ± 18 (16–79 years). 28 male and 21 female patients were included. 25 patients received a single iliosacral screw in S1. In 19 cases a screw in S1 and S2 was placed on the same side. Four patients got bilateral SI-screws in S1 and another patient received bilateral screw placement in S1 as well as an additional screw in S2. The mean operation time was 100 min ±103 (20–540 min). The isolated time for SI-placement was 50 min ± 20 (20–93 min). The mean radiation time was 3 min ± 1.7 (0.9–7.4 min) (n = 28). Altogether 84% of the screws showed an intraosseous position (grade 0). In the axial plane 7 screws perforated ventrally, 5 screws penetrated the adjacent neural foramen. In the frontal plane the screws showed greater variations, 61% deviated less than 5° (grade 0). In the study group 5 screws needed surgical revision because of either malplacement or postoperative pain. There were no infections or neurological complications. There was no statistical correlation between screw perforation and the body-mass-index. CONCLUSION. The computer-assisted implantation of iliosacral screws is a safe method in relation to screw perforation. It shows a high security and accuracy concerning the ventral and dorsal cortical perforation. There is a frequent angular deviation in the frontal view without appearance of screw perforation or mechanic, neurologic and angiologic complications. The minimal-invasive procedure shows a low postoperative revision rate

Percutaneous fixation with iliosacral screws has been shown to be a safe and reproducible method for the management of certain posterior pelvic injuries. However, the method is contraindicated in patients with sacral anatomical variations and dysmorphism. The incidence and the pattern of S1 anatomical variations were evaluated in 61 volunteers (35 women and 26 men) using MRI scans of the sacrum. S1 dimensions (12 parameters) in both the transverse and coronal planes were recorded and evaluated. Individuals were divided in four groups based on the S1 body size and the asymmetry of dimensions on the transverse and coronal planes. In 48 (78.6%) patients, dimensions in both planes were symmetrical despite the varying size of the S1 body. In 9 (14.8%) patients, coronal plane dimensions were disproportionally smaller compared to those of the transverse plane with a varying size of S1 body making effective iliosacral screw insertion a difficult task. In 2 (3.3%) patients there was a combination of large transverse plane and small coronal plane dimensions, with large S1 body size. A preoperative imaging study of S1 body size and coronal plane dimensions and an intraoperative fluoroscopic control of S1 dimensions on the coronal plane are suggested for safe iliosacral screw fixation

Percutaneous fluoroscopically assisted iliosacral screw insertion has become one of the most popular methods of stabilisation of the posterior aspect of the vertically unstable pelvis. Screw malpositioning rates range from 0 to 10 per cent. Screw malplacement can cause injury to the iliac and gluteal vessels, L4 to S1 nerve roots and sympathetic chain. We performed two radiographic studies on dry human bones to seek safe radiographic landmarks for insertion of iliosacral screws. Part 1. Two parallel linear densities are always present on lateral plain radiographs of the lumbosacral spine and pelvis. Using wire markers on pelvic bones, we accurately define the origin of these pelvic lines. Steel wires of different lengths were placed along the iliopectineal and arcuate lines of the pelvis. The shorter wire stopped at the anterior limit of the sacro-iliac joint. The longer wire extended further along the entire course of the medial border of the ilium to the iliac crest posteriorly. We demonstrate that each ‘ pelvic line ‘ represents the sharp bony ridge that forms the anterosuperior limit for insertion of iliosacral screws. Part 2. In a second experimenton dry pelvis, we inserted balloons filled with radio-opaque contrast medium into the spinal canal of the sacrum and exiting through the anterior and posterior sacral foramina on either side. Plain lateral radiographs and CT scan with reformatted images were obtained. We present a previously undescribed radiological sign on plain lateral radiographs of the lumbosacral spine. The inferior and posterior boundaries of the acorn sign are delineated

The purpose of this study was to assess the stability of a developmental pelvic reconstruction system which extends the concept of triangular osteosynthesis with fixation anterior to the lumbosacral pivot point. An unstable Tile type-C fracture, associated with a sacral transforaminal fracture, was created in synthetic pelves. The new concept was compared with three other constructs, including bilateral iliosacral screws, a tension band plate and a combined plate with screws. The pubic symphysis was plated in all cases. The pelvic ring was loaded to simulate single-stance posture in a cyclical manner until failure, defined as a displacement of 2 mm or 2°. The screws were the weakest construct, failing with a load of 50 N after 400 cycles, with maximal translation in the craniocaudal axis of 12 mm. A tension band plate resisted greater load but failure occurred at 100 N, with maximal rotational displacement around the mediolateral axis of 2.3°. The combination of a plate and screws led to an improvement in stability at the 100 N load level, but rotational failure still occurred around the mediolateral axis. The pelvic reconstruction system was the most stable construct, with a maximal displacement of 2.1° of rotation around the mediolateral axis at a load of 500 N

Background: Treatment of patients with partially or totally unstable pelvic ring disruptions includes primary anterior stabilization with an external fixator and additional posterior internal fixation. Iliosacral screws placed percutaneously under fluoroscopy or navigation guided techniques are widely accepted today to address the posterior lesions. Definite surgery is usually performed on a semi-emergent basis, whereas a delay of more than seven days in definite fixation is accompanied by a high rate of pulmonary complications, malreduction and infections. Purpose: To compare the outcome of patients with type B and C pelvic ring disruptions treated with immediate definite posterior fixation (within 24 hours) as compared to those treated with early fixation (24–96 hours from arrival). Patients and Methods: The medical records of 44 patients with type B and C pelvic ring disruptions were reviewed retrospectively. All posterior lesions were treated with closed reduction and internal fixation with percutaneously placed posterior iliosacral screws. Patients were divided into two groups, based on the time of definite fracture fixation from admittance to the ER. Immediate treatment included patients treated within 24 hrs of arrival (Group A), early intervention was defined as definite fracture fixation between 24–96 hrs from the patient’s arrival (Group B). Post operative radiographs (Pelvis AP, inlet and outlet) were used to assess the quality of final fracture reduction. Patient records were screened for demographic data, injury severity score and early morbidity and mortality. Results: Forty-four patients were treated between the years 1999–2002 due to posterior pelvic ring fractures. 70.5% of the patients were male, the majority of patients (41/44) were injured during motor vehicle accidents, two patients sustained work-related crush injuries and one patient was injured during a suicide attempt. Fracture patterns were classified according to the Tile classification, there were 31 type B and 13 type C fractures. Thirty patients were treated within 24 hrs of admittance to the ER (group A), fourteen were treated between 24 and 96 hrs from arrival (Group B). ISS averaged 19.5 in group A as compared to 17.8 in group B (p=0.74). Overall complication rates were low. Malreduction was noted in one patient (group A), one patient in each group became infected, S1 foraminal penetration occurred in two patients (Group A). Two patients in group A died due to complications not related to the orthopedic intervention. No significant difference was found between the complication rates in both groups (p=0.34). Conclusions: Immediate definite fixation of posterior pelvic lesions can be safely performed with posterior iliosacral screws. Comfortable nursing and early mobilization can be achieved without compromising the quality of fracture reduction and minimizes post-operative complications

Background. The suicidal jumper's fracture of the pelvis is a special form of sacrum fractures associated with high energy trauma. The typical H-type fracture pattern runs transforaminal on both sides with a connecting transverse component between S1 and S3. Due to the high-grade instability operative treatment is imperative. Aim of this study was to compare iliosacral double screwing (2×7,3mm canulated screw with 16mm thread) with spinopelvic internal fixation. Methods. Both methods were tested on 6 synthetic and 6 anatomical pelvises. After osteotomy and alternating osteosynthesis stability was tested with a universal testing machine (Zwick) in a simulated two-leg stand. Data were generated by a 3-dimensional computer-assisted ultrasoundsystem (Zebris©) (3 translational datasets x,y,z and 3 ankles). Testing was performed after preload of 50N and two setting cycles of 100N followed by a full load cycle of 150N. ASCII-data were then transferred to SPSS for statistical analysis. Results. Both experimental series showed similar results. There was a tendancy of less displacement when iliosacral screwing was performed. However, no statistical significance could be observed between both techniques. Discussion. Although the spinopelvic internal fixation is a more rigid system, the double screwing may compensate this as it interacts in the center of the fracture. We therefore think that iliosacral double screwing is an appropriate technique for stabilisation of this special fracture type. The possibility of percutaneous osteosynthesis and of its performance in a supine position, this procedure provides essential advantages for the operative treatment of polytraumatized patients