[Neurological damage in pelvic injuries: a continuous prospective series of 50 pelvic injuries treated with an iliosacral lag screw]

Value of Direct Decompression of Lumbosacral Roots in Sacral Fractures with Neurologic Deficit: Is It Mandatory?

Background

The value of direct decompression of neural structures to treat lumbosacral plexus injury associated with sacral fractures is still debatable. Direct decompression allows decompression of nerve roots by sacral laminectomy and removal of bone fragments in the spinal canal. In contrast, indirect decompression may offer similar neurological outcomes if good fracture reduction and correction of sacral kyphosis are achieved. In this comparative retrospective study, we analyzed differences between direct and indirect neurological decompression in terms of neurological recovery, complications, and functional outcome.

Methods

This study included 33 cases with spinopelvic dissociation with variable degrees of lumbosacral plexus injury. All cases were managed by spinopelvic fixation. Eighteen patients (group 1) had direct decompression of lumbosacral nerve roots while 15 patients (group 2) had indirect decompression.

Results

Initial sacral kyphosis, quality of fracture reduction, and postoperative residual kyphosis were the main factors that significantly affected functional and neurological outcome in both groups. The final neurological improvement was similar in both groups. No significant difference was observed between both groups in the residual Gibbons' score recorded in the last visit (p = 0.206). The final Majeed score also showed no significant difference between the two groups (p = 0.869).

Conclusions

Indirect decompression of sacral fractures showed similar final functional outcome and neurological recovery compared to direct decompression. Restoration of lumbosacropelvic stability and anatomic reduction seem to be the cornerstone for better functional outcome and neurological recovery rather than direct decompression of neural elements.

Early Clinical Result of Computerized Navigated Screw Fixation in Treatment of Fragility Pelvic Fracture

Introduction:

Minimal invasive fixation of fragility pelvic fracture is feasible with advancement of computerized navigation. However, the clinical outcomes compared with conservative care were seldom mentioned.

Method:

This is a retrospective study comparing the outcomes of elderly with stable pelvic fracture treated conservatively or operatively using computerized navigation. Outcome parameters included pain score, analgesics requirement, length of hospital stay and complication(s), if any.

Result:

Operations were performed in 15 patients from July 2017 to November 2018. A retrospective cohort of 37 patients who were treated conservatively was recruited. In the operative group, it showed a statistically significant reduction in analgesics consumption at 4-week time only. There was significant improvement in pain score at 1-week, 4-week and 3-month time. Patients showed earlier return to premorbid walking status. No major surgical complication was noted.

Conclusion:

Treating fragility pelvic fracture with computerized navigated screw fixation achieve better pain control, reduction in analgesics requirement and earlier mobilization.

Distance Between Reproductive Structures and the Insertion Point of the Retrograde Pubic Ramus Screw

OBJECTIVE

To identify the distance between the guidewire for a retrograde pubic ramus screw and critical reproductive structures in men and women.

METHODS

Twenty hemipelves from 10 fresh-frozen cadavers (pelvis to distal femur) were studied. The mean (±SD) age was 77 ± 6 years for the 5 male cadavers and 71 ± 9 years for the 5 female cadavers. A 2.8-mm guidewire for a cannulated screw was inserted from the parasymphyseal bone using fluoroscopic guidance. The soft tissue was dissected and measurements performed by the first author. In men, we measured the closest distances from the guidewire entry point to the contralateral spermatic cord and corpus cavernosum. In women, we measured the closest distances from the guidewire entry point to the base of the clitoral body and clitoral glans.

RESULTS

In male cadavers, mean distances were 8.8 ± 4.2 mm to the spermatic cord and 13 ± 6.7 mm to the corpus cavernosum. The guidewire did not penetrate these structures in any specimen. In female cadavers, mean distances were 12 ± 5.7 mm to the base of the clitoral body and 40 ± 8.2 mm to the clitoral glans. The guidewire also did not penetrate these structures.

CONCLUSIONS

The contralateral spermatic cord and corpus cavernosum in men and the base of the clitoral body in women are close to the pathway of the retrograde ramus screw guidewire. Careful identification of the entry point and avoidance of multiple attempts of guidewire insertion may reduce the risk of injury to these structures.

Do three-dimensional modeling and printing technologies have an impact on the surgical success of percutaneous transsacral screw fixation?

Objectives

This study aims to determine the role of computed tomography (CT)-derived templates, produced by three- dimensional (3D) modeling, image processing and printing technology, in percutaneous transsacral screw fixation and evaluate the effects of their use on surgical success.

Materials and methods

This prospective study conducted between June 2018 and December 2019 utilized 15 composite pelvis models for transsacral-transiliac screw fixation. For the procedure, modeled templates were utilized for wiring on the left side of the pelvis models, while the conventional method was performed on the right side of the pelvis models. In the computed tomography images acquired after wiring, appropriate wire position was evaluated.

Results

The placed wires held the S1 body appropriately in all of the procedures with or without template use. With the template use, the wires were placed appropriately in the surgical bone corridor suitable for the transsacral-transiliac screw fixation in all of the models. However, with the conventional methods, the wires were not placed in the safe surgical bone corridor in four models. The wire deviation angle in the axial plane was significantly lower in the template group (p=0.001), whereas it was not different between the template group and the conventional method group in the coronal plane (p=0.054). The amount of deviation from the ideal wire entry site was significantly reduced in the template group compared to the conventional method group (p=0.001).

Conclusion

With the use of 3D modeling and printing technology, CT-derived templates can be produced and utilized for transsacral screw fixation procedures and their use increases surgical success by reducing the surgical margin of error.

Chronic low back pain after lumbosacral fracture due to sagittal and frontal vertebral imbalance

PROBLEM AND HYPOTHESIS

Over time, some patients with unilateral or bilateral lumbosacral injuries experience chronic low back pain. We studied the sagittal and frontal balance in a population with these injuries to determine whether mismatch in the pelvic and lumbar angles are associated with chronic low back pain.

PATIENTS AND METHODS

Patients with posterior pelvic ring fractures (Tile C1, C2, C3 and A3.3) that had healed were included. Foreign patients and those with an associated spinal or acetabular fracture or nonunion were excluded. The review consisted of subjective questionnaires, a clinical examination, and standing A/P and lateral stereoradiographic views. The pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI), measured lumbar lordosis (LLm), T9 sagittal offset, leg discrepancy (LD) and lateral curvature (LC). The expected lumbar lordosis (LLe) was calculated using the formula LLe=PI+9°. We defined lumbopelvic mismatch (LPM) as the difference between LLm and LLe being equal or greater than 25% of LLe.

RESULTS

Fifteen patients were reviewed after an average follow-up of 8.8 years [5.4-15]. There were four Tile C1, five Tile C2, five Tile C3 and one Tile A3.3 fracture. Ten of the 15 patients had low back pain. The mean angles were: LLm 49.6° and LLe 71.9° (P=0.002), PT 21.3°, SS 44.1°, PI 62.9° in patients with low back pain and LLm 57.4° and LLe 63.2° (P=0.55), PT 13°, SS 43.1°, PI 54.2° in those without. LPM was present in 9 patients, 8 of who had low back pain (P=0.02). Six patients, all of whom had low back pain, had a mean LC of 7.5° [4.5-23] (P=0.02). The mean LD was 0.77cm.

DISCUSSION

The findings of this small study suggest that patients who experience low back pain after their posterior arch of the pelvic ring fracture has healed, have a lumbopelvic mismatch. Early treatment of these patients should aim to reestablish the anatomy of the pelvic base relative to the frontal and sagittal balance.

LEVEL OF EVIDENCE

IV.

Open Pelvic Fractures: Review of 30 Cases

BACKGROUND

Open pelvic fractures are rare but usually associated with a high incidence of complications and increased mortality rates. The aim of this study was to retrospectively evaluate all consecutive open pelvic fractures in patients treated at a single Level-1 Trauma Center during a 10-year interval.

PATIENTS AND METHODS

In a 10-year interval, 30 patients with a diagnosis of open pelvic fracture were admitted at a Level-1 Trauma Center. A retrospective analysis was conducted on data obtained from the medical records, which included patient's age, sex, mechanism of injury, classification of the pelvic lesion, Injury Severity Score (ISS), emergency interventions, surgical interventions, length of hospital and Intensive Care Unit stay, and complications, including perioperative complications and death. The Jones classification was used to characterize the energy of the pelvic trauma and the Faringer classification to define the location of the open wound. Among the survivors, the results were assessed in the last outpatient visit using the EuroQol EQ-5D and the Blake questionnaires. It was established the relationship between the mortality and morbidity and these classification systems by using the Mann-Whitney non-parametric test, with a level of significance of 5%.

RESULTS

Twelve (40%) patients died either from the pelvic lesion or related injuries. All of them had an ISS superior to 35. The Jones classification showed a direct relationship to the mortality rate in those patients (p = 0.012). In the 18 (60%) other patients evaluated, the mean follow-up was 16.3 months, ranging from 24 to 112 months. Eleven (61%) patients had a satisfactory outcome. The Jones classification showed a statistically significant relationship both to the objective and subjective outcomes (p < 5%). The Faringer classification showed a statistically significant relationship to the subjective, but not to the objective outcome. In addition, among the 18 patients evaluated at the last outpatient visit, the Faringer classification showed statistical significance on the need of colostomy (p = 0.001) in the acute phase of treatment.

CONCLUSION

We suggest the routine use of the Jones classification for the emergency room assessment and management of all open fractures of the pelvic ring. We believe the Faringer classification seems to be useful for the abdominal surgeons for the indication of gut transit derivation but not for the acute management of the bony component of an open pelvic fracture.

Osteosynthesis in sacral fracture and lumbosacral dislocation

Sacral fracture and lumbosacral hinge trauma are rare but serious lesions. Neurologic disorder is frequently associated, and nerve release may be required, with reduction and stabilization of the fracture. Management requires knowing the fracture lines and reduction maneuvers and the fixation techniques that may need to be associated. Three classifications allow these fractures to be well understood: the Roy-Camille classification identifies high transverse fractures and their displacement; the Denis classification identifies vertical fracture line location within the sacrum, which correlates with neurologic risk; and the Tile classification analyzes pelvic ring trauma when associated with the sacral fracture. Treatment, when surgical, requires careful patient positioning, sometimes on an orthopedic table. Reduction maneuvers are founded on the fracture classification. Isolated U-shaped fracture of the sacrum is to be distinguished from sacral fracture associated with pelvic ring lesion. Osteosynthesis may be lumbopelvic or restricted to the pelvic ring (sacroiliac or iliosacral). Open osteosynthesis allows reduction to be finalized by intraoperative maneuvers on the implant, while closed osteosynthesis requires perfect preoperative reduction. Complications are frequent and neurologic recovery is uncertain. Fatigue and osteoporotic fractures show little displacement and are good indications for cementoplasty, either isolated or associated to iliosacral screwing. In lumbosacral hinge trauma, and dislocation in particular, reduction surgery with fixation (usually 360°) is indicated. The present study details the analysis and classification of these fractures, the technical pitfalls of reduction and fixation, and treatment indications.

A simple approach for the preoperative assessment of sacral morphology for percutaneous SI screw fixation

BACKGROUND

Percutaneous sacroiliac screw fixation under fluoroscopic control is an effective method for posterior pelvic ring stabilization. However, sacral dysmorphism has a high risk of L5 nerve injury. This study describes a simple method for the preoperative assessment of the sacral morphology using CT scans with widely available tools.

MATERIALS AND METHODS

CT scans of 1000 patients were analyzed. True inlet, outlet, and lateral views of the sacrum were obtained using a two-dimensional reconstruction tool to align the sacrum in a reproducible manner. Corridor morphology in the inlet view was measured to calculate different morphological types: (1) Ascending type, (2) Horizontal type, and (3) Descending type. In a second step, the corridor was analyzed for the presence of an anterior indentation of the sacrum between the SI joint and the midsagittal plane with proximity to the nerve root L5, which, therefore, may be harmed during screw misplacement.

RESULTS

A notch was found in the majority of cases with relative frequencies ranging from 69 % (upper quartile of S1) to 95 % (upper quartile of S2). Descending types were, by far, the most frequent corridor type with one exception: In the upper quartile of S1, the ascending type was the most frequent corridor (71 %). Horizontal types were less frequent with a relative incidence between 2 and 14 %.

DISCUSSION

This study should increase the awareness for sacral dysmorphism, emphasize the importance of a preoperative assessment of the osseous corridor, and provide a simple method for the preoperative assessment with widely available tools.

Evaluation of Partial Cut-out of Sacroiliac Screws From the Sacral Ala Slope via Pelvic Inlet and Outlet View

STUDY DESIGN

An anatomic and radiographic study of placement of sacroiliac screws.

OBJECTIVE

The aim of this study was to quantitatively assess the risk of partial cut-out of sacroiliac screws from the sacral ala slope via inlet and outlet view.

SUMMARY OF BACKGROUND DATA

The partial cut-out of sacroiliac screws from the superior surface of sacral ala can jeopardize the L5 nerve root, which is difficult to identify on the pelvic inlet and outlet views.

METHODS

Computed tomography images of 60 patients without pelvic ring deformity or injury were used to measure the width (on inlet view) and height (on outlet view) of the sacral ala. The angle of the sacral ala slope was measured on lateral view. According to the measured parameters, the theoretical safe trajectories of screw placement were calculated using inverse trigonometric functions. Under fluoroscopic guidance, a sacroiliac screw was placed close to the midline on both inlet and outlet views, including posterosuperior, posteroinferior, anterosuperior, and anteroinferior regions to the midline. The incidence of screw partial cut-out from the superior surface of sacral ala was identified.

RESULTS

The measured widths and heights of the sacral alas were 28.1 ± 2.8 and 29.8 ± 3.1 mm, respectively. The average angle between the superior aspect of the S1 vertebral body and the superior aspect of the sacral ala was 37.2 ± 2.5 degrees. The rate of partial cut-out of the screws from the superior surface of sacral ala slope was 12.5% (5/40) in posterosuperior, 0% (0/40) in posteroinferior, 70% (28/40) in anterosuperior, and 20% (8/40) in anteroinferior.

CONCLUSION

To avoid the risk of partial cut-out from sacroiliac screw placement, more precise description should be added to the conventional description: the sacroiliac screws should be placed at the inferior half portion on outlet view and at the posterior half portion on inlet view.

LEVEL OF EVIDENCE

4.

Assessment of pelvic injuries treated with ilio-sacral screws: injury severity and accuracy of screw positioning

PURPOSE

The aim of this study was to analyse possible indicative parameters for percutaneous ilio-sacral stabilisation and to identify parameters associated with screw misplacement.

METHODS

Cohort study, level I trauma centre.

INCLUSION CRITERIA

(1) unstable pelvic injury, (2) percutaneous ilio-sacral screws placement.

EXCLUSION CRITERIA

(1) sacral dysmorphy, (2) failed closed reduction, (3) navigated techniques. Indicative parameters were age, gender, body mass index, number of screws, screw angulation, fracture type and injury severity. End points were ilio-sacral screw position and associated complications. Screw placement accuracy was graded as follows: grade 0, no perforation; grade 1, perforation <2 mm; grade 2, perforation from 2 to 4 mm; grade 3, ≥4 mm perforation.

RESULTS

Between March 2008 and March 2013, 102 (53 women) patients were included (mean age, 48.5 ± 21.4 years). The Injury Severity Score (ISS) and New Injury Severity Score (NISS) were 18.9 ± 9.9 and 22.3 ± 22.3, respectively. The positions of 137 ilio-sacral screws were analysed. Of all screws, 87.6 % (120) were placed satisfactory (<2 mm perforation). The incidence of screw misplacement was significantly higher in the case of two unilateral S1 screws compared with a single screw (failure rate: two unilateral screws 23.1 % vs single screw 7.0 %; p < 0.05). Screw perforation anterior to the lateral mass (in-out-in) represented the most frequent malposition. Revision was necessary in three cases due to malpositioning. Furthermore, no major complication occurred.

CONCLUSIONS

We conclude, that twofold ilio-sacral screw positioning from one side increases the risk for screw misplacement. In this case, alternative techniques like navigation should be considered. Anterior screw perforation represents a common problem with a high incidence and warrants particular attention.

The influence of injecting an epidural contrast agent into the sacral canal on the fluoroscopic visibility of bony landmarks for sacroiliac screw fixation: a feasibility study

OBJECT

In sacroiliac screw fixation of unstable pelvic injuries in geriatric patients, poor bone quality often obscures important bony landmarks in fluoroscopic images. The authors analyzed the feasibility of injecting a transhiatal contrast agent (CA) into the sacral canal to improve fluoroscopic visualization in the sacral epidural space.

METHODS

Eight fresh cadaveric whole-body specimens from human donors whose mean age at the time of death was 78 years (range 69-87 years) were used. First, to identify bony landmarks without CA enhancement, the authors acquired fluoroscopy images of the native sacral canal, using lateral, inlet, and outlet projections. Through puncture of the sacral hiatus, 8-10 ml of CA was injected into the epidural space. Fluoroscopy images were then acquired in the standard pelvic views to identify the bony landmarks. To assess the effect of the CA enhancement, visibility of the landmarks was assessed before and after CA injection. Each identified landmark was scored as 1, and summative landmark scores of up to 10 were determined for each specimen.

RESULTS

The cadaveric specimens were representative of bone structures in the geriatric population. In all specimens, epidural CA injection enhanced the fluoroscopic visualization of the sacral canal and of the S-1 foramina. The enhancement increased the total bony landmark score from 5.9 (range 4-8) without CA injection to 8.1 (range 6-10) after CA injection. Considering only intrasacral landmarks, the score was increased from 1.5 to 3.

CONCLUSIONS

Injection of a transhiatal epidural CA improves fluoroscopic imaging of the sacral canal and of the neural foramina. Hence, this technique could be applied to help the surgeon identify anatomical landmarks during sacroiliac screw fixation in geriatric patients.

Sacroiliac screw fixation: A mini review of surgical technique

The sacral percutaneous fixation has many advantages but can be associated with a significant exposure to X-ray radiation. Currently, sacroiliac screw fixation represents the only minimally invasive technique to stabilize the posterior pelvic ring. It is a technique that should be used by experienced surgeons. We present a practical review of important aspects of this technique.

In lumbosacral plexus injuries can we identify indicators that predict spontaneous recovery or the need for surgical treatment? Results from a clinical study on 72 patients

Background

Post-traumatic lumbosacral plexus injuries seem to be rare events, spontaneously recovering in high percentage: as surgery is often challenging and results in poor outcome, many Authors have advocated conservative treatment only. Nevertheless surgery should not be ruled out: in invalidating injuries, it can restore basic function in the lower extremities.

Therefore, it might be necessary to establish guidelines for the management and the indication to surgery in such cases.

This study aims to identify indicators predicting spontaneous recovery or the need for surgery.

Method

The clinical and radiological data of 72 patients with a post-traumatic lumbosacral plexus injury were reviewed. A follow up equal or superior to 3 years is available in 42 cases.

Results

Lumbosacral plexus injuries mostly occurred during road accidents. The incidence of associated lesions was relevant: bone injuries were found in 85% of patients, internal lesions in 30% and vascular injuries in 8%.

Lumbosacral trunk and sacral plexus palsies were the most frequent injury patterns.

Root avulsions were revealed in 23% of cases and only in sacral plexus and complete lumbosacral plexus injuries: L5 and S1 were the roots more prone to avulsions.

About 70% of cases recovered spontaneously, mostly in 18 months. Spontaneous recovery was the rule in lumbar plexus and lumbosacral trunk injuries (where root avulsions never occurred) or in sacral and complete lumbosacral plexus palsies due to compression injuries.

The causative mechanism correlated with the injury pattern, the associated bone injury being often predictive of the severity of the nerve injury.

Lumbosacral plexus injuries occurred in car crashes were generally associated with fractures causing compression on the nerves, thus resulting in injuries often amenable of spontaneous recovery.

Motorcycle accidents implied high kinetic energy traumas where traction played an important role, as the high percentage of sacroiliac joint separations demonstrated (found in more than 50% of cases and always associated to root avulsions).

Loss of sphincteral control and excruciating leg pain were also invariably associated with avulsions.

Conclusions

Clinical and radiological data can help to predict the occurrence of spontaneous recovery or the need for surgery in post-traumatic lumbosacral plexus injuries.

The influence of sacral morphology on the existence of secure S1 and S2 transverse bone corridors for iliosacroiliac screw fixation

Sacroiliac (SI) screw fixation for unstable pelvic fractures stands out as the only minimally invasive method among all other ORIF procedures. A strictly transverse screw trajectory is needed for central or bilateral fracture patterns up to a complete iliosacroiliac fixation. However, secure screw insertion is aggravated by a narrow sacroiliac bone stock. This study investigates the influence of a highly variable sacral morphology to the existence of S1 and S2 transverse corridors. The analysis contained in this study is based on 125 CT datasets of intact human pelvises. First, sacral dysplasia was identified using the "lateral sacral triangle" method in a lateral 3-D semi-transparent pelvic view. Second, 3-D corridors for a 7.3mm screw in the upper two sacral levels were visualised using a proprietary IT workflow of custom-made programme scripts based on the Amira(®)-software. Shape-describing measurement variables were calculated as output variables. The results show a significant linear correlation between ratioT and the screw-limiting S1 isthmus height (Pearson coefficient of 0.84). A boundary ratio of 1.5 represented a positive predictive value of 96% for the existence of a transverse S1-corridor for at least one 7.3mm screw. In 100 out of 125 pelvises (80%), a sufficient S1 corridor existed, whereas in 124 specimens (99%), an S2 corridor was found. Statistics revealed significantly larger S1 and S2 corridors in males compared to females (p<0.05). However, no gender-related differences were observed for clinically relevant numbers of up to 3 screws in S1 and 1 screw in S2. The expanse of the S1 corridor is highly influenced by the dimensions of the dysplastic elevated upper sacrum, whereas the S2 corridor is not affected. Hence, in dysplastic pelvises, sacroiliac screw insertion should be recommended into the 2nd sacral segment. Our IT workflow for the automatic computation of 3-D corridors may assist in surgical pre-operative planning. Furthermore, the workflow could be implemented in computer-assisted surgery applications involving pelvic trauma.

Lumbar plexus injury in an anterior fracture dislocation of sacroiliac joint: a case report and review of literature

Displaced unstable pelvic fractures are commonly associated with disruption of the osteoarticular junction of the sacroiliac joint. Posterior sacroiliac dislocation are commonly reported but there are only few reports the anterior type of sacroiliac dislocation where the iliac bone fractures and displaces anterior to sacrum, often in combination with fractures of pubic rami and symphyseal injuries. We present a case of an anterior type of sacroiliac fracture dislocation which was associated with a lumbar plexus injury involving both motor and sensory components. Preoperative neurological assessment was done by MRI scan. The tented nerve roots were explored and decompressed surgically, and sacroiliac fixation was done after reduction in the fracture and joint.

CT-based 3-D visualisation of secure bone corridors and optimal trajectories for sacroiliac screws

Sacroiliac screw (SI) fixation represents the only minimally invasive method to stabilise unstable injuries of the posterior pelvic ring. However, it is technically demanding. The narrow sacral proportions and a high inter-individual shape variability places adjacent neurovascular structures at potential risk. In this study a CT-based virtual analysis of the iliosacral anatomy in the human pelvis was performed to visualise and analyse 3-D bone corridors for the safe placement of SI-screws in the first sacral segment. Computer-aided calculation of 3-D transverse and general SI-corridors as a sum of all inner-bony 7.3-mm screw positions was done with custom-made software algorithms based on CT-scans of intact human pelvises. Radiomorphometric analysis of 11 CT-DICOM datasets using the software Amira 4.2. Optimal screw tracks allowing the greatest safety distance to the cortex were computed. Corridor geometry and optimal tracks were visualised; measurement data were calculated. A transverse corridor existed in 10 pelvises. In one dysmorphic pelvis, the pedicular height at the level of the 1st neural foramina came below the critical distance of 7.3mm defined by the outer screw diameter. The mean corridor volume was 45.2 cm3, with a length of 14.9cm. The oval cross-section measured 2.8 cm2. The diameter of the optimal screw pathway with the greatest safety distance was 14.2mm. A double cone-shaped general corridor for screw penetration up to the centre of the S1-body was calculated bilaterally for every pelvis. The mean volume was 120.6 cm3 for the left side and 115.8 cm3 for the right side. The iliac entry area measured 49.1 versus 46.0 cm2. Optimal screw tracks were calculated in terms of projected inlet and outlet angles. Multiple optimal screw positions existed for each pelvis. The described method allows an automated 3-D analysis with regard to secure SI-screw corridors even with a high number of CT-datasets. Corridor visualisation and calculation of optimal screw tracks trains the visual thinking of the surgeon and can improve pre-operative planning. Prospectively, the introduced method can be implemented in computer-assisted surgery applications involving pelvic trauma.

The percutaneous stabilisation of the sacroiliac joint with hollow modular anchorage screws: a prospective outcome study

PURPOSE

The use of percutaneous iliosacral screw fixation as a treatment of sacroiliac joint pain has been reported to be successful. This study was a prospective single surgeon series to evaluate the short-term outcomes of patients who underwent percutaneous sacroiliac joint stabilisation.

METHODS

Between July 2004 and February 2011, 73 patients underwent percutaneous sacroiliac joint fusion in our unit. All patients completed a short form (SF)-36 questionnaire, visual analogue pain score and Majeed scoring questionnaire prior to treatment and at last follow-up.

RESULTS

55 patients (9 male and 46 female) completed follow-up. The average follow-up period was for 36.18 months (range 12-84). The mean preoperative SF-36 scores were 26.59 for physical health and 40.38 for mental health. The mean postoperative SF-36 scores were 42.93 for physical health and 52.77 for mental health. The mean visual analogue pain scores were 8.1 preoperative and 4.5 postoperative. The mean pelvic specific scoring were 36.9 preoperative and 64.78 postoperative. We noted that patients who had previous instrumented spinal surgery did significantly worse than those who had not. We had two nerve root-related complications.

CONCLUSION

We conclude that in selected patient group who respond positively to CT-guided injection, a percutaneous SI joint stabilisation is beneficial in effecting pain relief and functional improvement.

Ureteral injury after percutaneous iliosacral fixation: a case report and literature review

We report a case of right ureter injury in an 11-year-old girl after a percutaneous iliosacral screwing with non-computer-assisted fluoroscopic guidance. The indication was a pelvic ring fracture, C1-1 in the Tile modified AO classification (J Am Acad Orthop Surg. 1996;4:143-151). The mechanism was a ski accident. A percutaneous iliosacral screwing was performed to stabilize the right iliac wing fracture. Twelve days after the initial trauma, a right ureter tear was highlighted, just opposite the fourth lumbar vertebra. Uneventful spontaneous healing of the ureteral injury site occurred following double J-stent catheterization.

The lateral sacral triangle--a decision support for secure transverse sacroiliac screw insertion

Sacroiliac (SI) screw fixation represents an effective method to stabilise pelvic injuries. However, to date neither reliable radiological landmarks nor effective anatomical classifications of the sacrum exist. This study investigates the influence of variability in sacral shape on secure transverse SI-screw positioning. Furthermore, consistent correlations of these anatomical conditions are analysed with respect to standard planar pelvic views. For shape analysis, 80 human computed tomography data sets were segmented with the software Amira 4.2 to obtain 3D reconstructions. We identified anatomical conditions (ACs) according to the extent of the effect on the bony screw pathway. Subsequently, the pelvis was spatially aligned using representative bone protuberances in order to create standard Matta projections. In each view, the ACs were described in terms of distance from bone landmarks. Three-dimensional shape analysis revealed the height of the pedicular isthmus (PH) as the limiting variable for secure screw insertion. The lateral and outlet views allowed an orthogonal projection of PH. In the lateral view, the ratio of the lateral sacral triangle framed by the S1 body height and width showed a high correlation to PH (p = 0.0001). A boundary ratio of 1.5 represented a reliable variable to determine whether or not a screw can be inserted (positive predictive value: 97%). In the outlet view, the distance between the S1 endplate and the SI joint top level (EJ) strongly correlated with PH (p = 0.0001). With EJ 0 mm, screw insertion was possible in all cases (100%). SI-screw insertion requires a well-planned procedure. Orientation of the sacral pedicle is of extreme relevance. A narrow sacroiliac channel and high sacral shape variability limit secure screw placement. However, no determining parameters exist, allowing accurate prediction of secure screw insertion based on X-rays or fluoroscopy. The lateral sacral triangle in the lateral view represents a simple and accurate preoperative method of support for the surgeon's decision to undertake this procedure. No additional technical effort is necessary. A boundary ratio of 1.5 predicts a sufficient bone stock for at least one 7.3 mm screw. Furthermore, the evaluation of the outlet projection can be used to assess the safety of the operation. Basically, a preoperative lateral pelvic image should be mandatory.

Anterior hip subluxation following fixation of a T-shaped acetabular fracture through an extended iliofemoral approach

We report the case of a 34-year-old female patient who, six week following her acetabular fracture ORIF through an extended iliofemoral approach, presented with anterolateral incomplete dislocation of the femoral head. In the absence of joint incongruence as demonstrated on radiographs and CT images, a capsular tightening was performed via the anterior Hueter approach. This capsular plasty stabilized the hip for 2 years, but gradual osteoarthritis deterioration resulted in the need for arthroplasty. At the 2-year follow-up, this secondary arthroplasty showed satisfactory result. The substantial muscle exposure of the lateral aspect of the acetabulum and the circumferential capsulotomy related to the use of the iliofemoral approach were retained as factors promoting this complication. In case early postoperative mobilization is impossible, temporarily maintaining the limb in abduction and flexion can be recommended after an extended iliofemoral approach with circumferential capsulotomy.

Iatrogenic femoral neuropathy: two cases and literature update

Iatrogenic femoral neuropathy is an uncommon surgical or obstetric complication that may be underreported. It results from compression, stretch, ischemia, or direct trauma of the nerve during hip arthroplasty, self-retaining retractor use in pelvicoabdominal surgery, lithotomy positioning for anesthesia or labor, and other more rare causes. Decreasing incidence of this complication after abdominal and gynecologic surgery but increase in its absolute numbers after hip arthroplasty has emerged over the last decade. We describe two illustrative cases related respectively to lithotomy positioning and self-retaining retractor use. The variability in clinical presentation of iatrogenic femoral nerve lesions, some new insights in their diverse pathophysiology, and in the diagnostic and treatment options are discussed with an update from the literature.

Risk factors for lumbosacral plexus palsy related to pelvic fracture

STUDY DESIGN

A retrospective study.

OBJECTIVE

We assessed risk factors for lumbosacral plexus palsy related to pelvic fracture that can be evaluated during the acute injury phase with diagnostics such as computed tomography (CT).

SUMMARY OF BACKGROUND DATA

Many patients with pelvic fracture are in vital shock, with polytrauma and loss of consciousness, making an accurate neurologic examination very difficult in the emergency room.

METHODS

This study included 22 patients who had AO classification type B or C pelvic fractures. The 22 patients had 27 posterior osteoligamentary lesions. The average injury severity score (ISS) was 27.5 (range, 16-50). Age, sex, ISS, suicidal jump, longitudinal displacement, sacral transverse fracture, pubic fracture, lumbar transverse process fracture, type of pelvic fracture (AO), and type of sacral fracture (Denis) were examined for a correlation with the lumbosacral plexus palsy. Using coronal reconstruction CT, we considered a 10 mm or greater displacement at the sacrum or sacroiliac joint to be a longitudinal displacement. Transverse sacral fracture was diagnosed by sagittal reconstruction CT.

RESULTS

Of the 22 patients, 5 (22.7%) had lumbosacral plexus palsy (8 of 27 pelvic fractures) detected during treatment. The incidence of lumbosacral plexus palsy was not related to age, sex, ISS. Incidence of palsy was significantly higher when the patient's affected side had longitudinal displacement. Patients who had made a suicidal jump or had a sacral transverse fracture also had a significantly higher risk for lumbosacral plexus palsy. Palsy was not related to the type of pelvic fracture (AO) or sacral fracture (Denis).

CONCLUSION

In this study, longitudinal displacement of the pelvis, transverse sacral fracture, and trauma from a suicidal jump were risk factors for lumbosacral plexus palsy. These risk factors were helpful in our examination of patients who had severe pelvic fracture with loss of consciousness.

[Bony sacroiliac corridor. A virtual volume model for the accurate insertion of transarticular screws]

BACKGROUND

Minimally invasive sacroiliac (SI) screw fixation carries a high risk for implant malposition. Only idealised shape conceptions of the safe bony corridor exist.

METHODS

Two SI corridor models were generated based on a 3D CT reconstruction of a human pelvis. Therefore two penetration depths of the screws into the sacrum were defined.

RESULTS

By inserting screws into the centre of the first sacral body an osseous volume of 121 cm3 and an iliac entrance area of 53 cm2 were utilizable. Screw positioning beyond the opposite sacral isthmus leads to a reduction of the bony volume to 72 cm3 (60%) and a decrease of the iliac screw entrance to 20 cm2 (38%).

CONCLUSION

The computed realistic 3D models provide exact references to confining bone structures for safe screw positions. The implementation of a software algorithm for fully automated calculation of such volumes based on fluoroscopic or CT images could enhance the performance of computer-assisted navigation systems.

[Biomechanical comparison of different stabilisation devices for transforaminal sacral fracture. Is an interlocking device advantageous?]

BACKGROUND

Reliable osteosynthesis for fractures in the different regions of the human pelvis are described in the literature while there is no common and satisfying treatment for unstable sacral fractures. Because of the posterior pelvic rings special anatomic conditions a local plate osteosynthesis seems to be advantageous. In many fields of modern fracture treatment locking implants show superior results. The prototype of a local locking plate osteosynthesis was compared to a common local plate and two sacroiliac screws.

METHODS

The implants were tested using six plastic models of the pelvis and three embalmed human specimens. A Tile C1 fracture was created by disruption of the pubic symphysis and a transforaminal osteotomy. The specimens were exposed to axial loading in an upright single-leg stance with a maximum of 800 N for the plastic models and 200 N for the human specimens. An ultrasonic-based measuring system recorded translations (X, Y, Z) and rotations (alpha, beta, gamma). Parameters such as pattern of motion, translation/rotation, load to failure and remaining dislocation were evaluated.

RESULTS

Concerning most of the evaluated parameters the local plate osteosynthesis was inferior compared with two sacroiliac screws. There were no significant differences between the locking implant and the local plate osteosynthesis. Compared with the two sacroiliac screws the locking implant shows biomechanically equal results but allows greater anterior rotation and remaining dislocation. Because of the lower bone quality, the results from the anatomic specimen tested were not utilisable.

CONCLUSIONS

The locking implant is biomechanically an alternative compared with two sacroiliac screws. Problems occurred due to the preset direction of the locking head screws.

Technik der perkutanen SI-Verschraubung mit Unterstützung durch konventionellen C-Bogen

BACKGROUND

During percutaneous iliosacral screw fixation, fluoroscopy with a conventional C-arm X-ray unit is still the standard procedure for intraoperative orientation. Lateral sacral images in combination with the inlet and outlet view are always necessary. Nevertheless, the complex pelvic anatomy makes it difficult to prevent malpositioning of screws.

OPERATIVE TECHNIQUE

Defining the correct entry into the bone is the decisive step for ideal screw placement. The better this is defined, the larger safety margins will be concerning cortical perforation by the screws. In the lateral view, an entry ventral to the sacral canal has to be avoided as well as an entry into the cranial half of the first sacral vertebra. To improve the surgeon's three-dimensional orientation with the help of his personal experience and two-dimensional images, it is recommended to place the tip of the screws in the center of the sacrum (in AP view) whenever possible. Routinely performed postoperative CT imaging of 24 screws, consecutively implanted according to the standards described, revealed no case of malpositioning.

CONCLUSION

Standard X-ray views in combination with standardized aiming of screw entry position and final screw thread position enable the surgeon to find the "safe zone" for iliosacral screw insertion and to prevent iliosacral screw malpositioning with high accuracy.