Lumbopelvic Fixation Research Articles

Modified Iliac Screw in Lumbopelvic Fixation After Sacral Tumor Resection: A Single-Center Case Series.

Traditional iliac screw, S2-alar iliac screw, and modified iliac screw are the 3 common techniques for lumbopelvic fixation. The application of the modified iliac technique in sacral spinal tumors has been rarely reported. To report the feasibility and safety of modified iliac screws after sacral tumor resection and their preliminary clinical outcomes. Twenty-seven patients who underwent sacral tumor resection with modified iliac screw fixation between August 2017 and August 2021 at our center were clinically and radiographically evaluated. A total of 59 iliac screws were inserted by freehand according to the anatomic landmarks. The mean operation time was 207 minutes (range, 140-435 minutes). The average estimated blood loss was 1396 mL (300-4200 mL). Computed tomography scans showed that 2 (3.4%) screws penetrated the iliac cortex, indicating a 96.6% implantation accuracy rate. There were no iatrogenic neurovascular or visceral structure complications observed. The mean minimal distances from the screw head to the skin were 24.9 and 25.8 mm on the left and right sides, respectively. The mean minimal distances from the screw head to the horizontal level of the posterior superior iliac spine were 7.9 and 8.3 mm on the left and right sides, respectively. Two patients (7.4%) underwent reoperation for wound infection. At the latest follow-up, no patient had complications of screw head prominence, pseudarthrosis, or instrument failure. The modified iliac screw is characterized by its minimal invasiveness and simplicity of placement. It is an ideal alternative for lumbopelvic fixation after sacral tumor resection.

18 months results of a reinforced lumbopelvic fixation technique

18 months results of a reinforced lumbopelvic fixation technique

Fragility fractures of the pelvis: An update

Fragility fractures of the pelvis (FFP) are becoming a frequent diagnosis in clinical practice. FFP typically appear after a low-energy trauma in female patients of old age with osteoporosis. The characteristics of FFP differ from pelvic injuries after high-energy trauma. The new comprehensive FFP-classification reflects the specific morphology of the fractures and distinguishes different categories of instability. Key factors for operative treatment are the degree of instability, late presentation, and failure of conservative treatment. It is recommended to treat FFP type I and FFP type II conservatively, whereas FFP type III and FFP type IV should be treated operatively. Surgical stabilization should be as minimal-invasive as possible. Alternatives for the posterior pelvic ring are ilio-sacral screw osteosynthesis with or without cement augmentation, the transiliac internal fixator, the trans-sacral bar, and lumbopelvic fixation. Alternatives for the anterior pelvic ring are the retrograde transpubic screw, the internal fixator, and plate osteosynthesis. The length of hospital stay and complication ratio is higher after operative treatment, whereas mortality is lower than in the conservative group. Quality of life and mobility are reduced in all patients, independent of the classification and treatment type. The FFP-classification and the treatment recommendations provide a framework for searching for the best solution for each individual patient.

Результат успешного лечения пациентки с сочетанной травмой, включающей оскольчатый переломовывих крестца, осложненный каудопатией

Introduction Combined injury, as a cause of death, occupies a central place in different age groups and is common for individuals ages 50 and younger. Most sacral fractures are traditionally repaired with screw or plate. However, the fixation can be unreliable in atypical anatomy of the upper sacral segment, U-shaped and H-shaped fractures, compression of nerve structures and failed fixation. Material and methods Reported is a case of a 29-year-old patient who suffered a severe concomitant injury including comminuted fracture-dislocation of the sacrum complicated by caudopathy. Results A good clinical and anatomical result was obtained. She developed a complete regression of neurological symptoms. The patient could ambulate without additional support. The function of the pelvic organs was restored. Discussion For a comparison, two methods were presented: lumbopelvic fixation using two rods and a transverse buckle and triangular fixation with a rod and an additional iliosacral screw. Lumbopelvic fixation is a surgical procedure for unstable pelvic ring injuries that allows immediate weight-bearing. Biomechanical tests showed greater primary stability with triangular lumbopelvic fixation than iliosacral fixation with no stress to the injured area. Bilateral lumbopelvic fixation with a transverse buckle allowed secure fixation of the lumbopelvic junction for fracture healing, protection of the sacroiliac joints preventing the development of transitional kyphosis and maintaining the spine balance with careful surgical handling of the soft tissues.

Substantation of the method of lumbo-pelvic fixation in verically unstable fractures of the sacrum

Background. According to the literature and our own observations, there is an increase in the number of victims of young, ablebodied age with severe injuries to the pelvic structures. Despite numerous developments and studies in this area, high mortality and a high percentage of unsatisfactory treatment results remain. The publication reflects the advantages of using bilateral lumbopelvic fixation in the treatment of injuries to the cross. Load calculation, biomechanical modeling of damages and displacing factors are presented. Bilateral lumbopelvic fixation has proven to be a reliable method capable of providing reliable fixation of the fracture at all stages of treatment. Aim. To substantiate and test modified lumbopelvic stabilization of the pelvic ring in patients with vertically unstable (C1-2-3 according to Tile M.) sacral fractures. Material and methods. Based on the treatment of 20 patients with severe sacral fractures, it was proved that the best result was achieved with bilateral lumbopelvic stabilization. The use of the author's version (RF Patent No. 2684870 "Method of fixation in unilateral unstable sacral fractures") of osteosynthesis is presented on the example of the treatment of multiple pelvic trauma, a good clinical result was obtained, and neurological symptoms were stopped. Results. Lumbar-iliac osteosynthesis for vertically unstable sacral fractures is the optimal method of fixation. The distribution vector of the levers of the latch corresponds to the biasing force, which ensures maximum reliability of the synthesis. The method, if necessary, creates conditions for decompression of the roots, prevents the early development of arthrosis of the sacroiliac joints. Using it allows you to maintain or correct the sagittal and frontal balance of the spine. The use of bilateral 8-screw lumboiliac fixation with the installation of a transverse tie is recommended, since unilateral fixation or a decrease in the number of fixing elements can lead to loosening of the fixator. Conclusion. Based on biomechanical modeling and the results of treatment of patients with severe injuries of the posterior pelvic ring, the effectiveness of the proposed method of lumbopelvic fixation was proven.

The surgical management of highly unstable fragility fractures of the sacrum with spinopelvic dissociation: A case series and proposal of a surgical treatment algorithm

IntroductionU- and H-shaped fragility fractures of the sacrum (FFP IVb) are unstable fractures. Non-operative treatment may be associated with impaired walking abilities, chronic pain and the potential loss of independency. However, different treatment options are still controversially debated. The aim of surgical treatment includes sufficient fracture stability for immediate full weight bearing and good pain control postoperatively. A new surgical treatment algorithm was developed. This algorithm was evaluated in a cohort of geriatric patients with FFP type IVb regarding surgical complications and patient-related outcome. MethodsRetrospective case series. Patients ≥65 years, admitted with FFP IVb between 01/2017 and 12/2020 were included. Pelvic CT was performed and the surgical technique was chosen according to the proposed surgical treatment algorithm. For this algorithm, the technique of fracture stabilisation was adapted to sacral anatomy and the specific fracture pattern to minimize the impact of surgery and postoperative complications without compromising a sufficient fracture stability. Pain levels, complications and surgical revisions were recorded. Level of independency, walking abilities and -aids were compared 3- and 12- months postoperatively to the pre-injury situation. ResultsTwenty-three patients were included. Outcome parameters could be obtained in 20 patients (85%) after three months and in 18 patients (78%) patients one year postoperatively. All patients were treated according to the algorithm. Sixteen patients received two transilio-transsacral screws (TI-TSS), whereas either lumbopelvic fixation (LPF) combined with a TI-TSS or bilateral ilio-sacral screws (ISS) was performed four times. Three patients underwent bilateral ISS into S1 with one TI-TSS into S2. Three days postoperatively, median pain VAS was 2 (0-8) compared to 7 (4-10) before surgery. One loosened TI-TSS was removed six weeks postoperatively. Three-month mortality was 14% (n=3). At one-year follow-up, all patients regained their pre-injury level of walking abilities. ConclusionsRestoration of walking abilities, preservation of independency and efficient pain control can be achieved with surgical fixation of FFP type IVb fractures. With the proposed surgical algorithm, the fixation techniques are adapted to the fracture pattern to minimize the surgical burden. Level of EvidenceIV

Lumbopelvic Fixation with Bridged Distal Iliac Screws for Vertically Unstable Sacral Fractures.

The purpose of this study is to evaluate preliminary outcomes of vertically unstable sacral fractures treated by lumbopelvic fixation (LPF) augmented transiliac bridged screws. From April 2017 to December 2019, fifteen consecutive patients with vertically unstable sacral fractures who had undergone LPF augmented transiliac bridged screws were enrolled. The radiological assessment included standard lumbopelvic x-rays and pelvic computed tomography (CT) to evaluate the lumbosacral angle (LSA), sacral kyphosis angle (SKA), lumbar lordosis angles (LLA) and Matta's reduction criterias (MRC). Clinical and neurologic impairment outcomes were evaluated by the Majeed grading scale (MGS) and Gibbons criterias, respectively. All patients were followed for an average of 18months (range, 14-25). All sacral fractures eventually healed and implant failure did not occur in any patient, though there were two patients with a loss of reduction (< 5mm) during the follow-up period. According to the MRC, the results were excellent on 14 sides, good on five sides, and fair on one side. The MGS mean score was 82 points (range, 49-98 points); the results were excellent in nine cases, good in four cases, and fair in two cases. There was no statistically significant difference in SKA and LLA in preoperative and postoperative final controls. The preoperative and postoperative LSA were 72 ± 13.9 and 44.1 ± 11.3, respectively, and a statistically significant improvement was observed (p = 0.01). In vertically unstable sacrum fractures, we believe that LPF augmented with transiliac bridging technique may expedite the reduction of vertical sacrum fracture and offers a reinforced fixation choice.

Rates of Loosening, Failure, and Revision of Iliac Fixation in Adult Deformity Surgery.

Retrospective cohort review of a prospective multicenter database. Identify rates and variations in lumbopelvic fixation failure after adult spinal deformity (ASD) correction. Traditional iliac (IS) and S2-alar-iliac (S2AI) pelvic fixation methods have unique technical characteristics for their application, and result in varied bio-mechanical and anatomic impact. These differences may lead to variance in lumbopelvic fixation failure types/rates. ASD patients undergoing correction with more than five level fusion and pelvic fixation, separated by pelvic fixation type (IS vs. S2AI). Fixation fracture or loosening assessed radiographically (Figure 1). Multivariate logistic regression, accounting for significant confounders, was used to examine differences between the two groups for screw loosening/fracture, rod fracture, and revision surgery. Level of significance set at P< 0.05. Four hundred eighteen of 1422 patients were included (IS = 287, S2AI = 131). The groups had similar age, body mass index (BMI), baseline comorbidities, number of levels fused (P>0.05), baseline health related quality of life measures (HRQLs) (short form survey-36, Oswestry Disability Index [ODI], Scoliosis Research Society [SRS-22], numeric rating scale [NRS] leg and back, P>0.05) and deformity (pelvic tilt [PT], pelvic incidence-lumbar lordosis [PI-LL], and sagittal vertical axis [SVA], P> 0.05). The IS group had more unilateral fixation versus S2AI (12.9% vs. 6%; P = 0.02). The overall lumbopelvic fixation failure rate was 23.74%. Pelvic fixation (13.4%) and S1 screw (2.9%) loosening was more likely with S2AI (odds ratio [OR] 2.63, P = 0.001; OR 6.05, P = 0.022). Pelvic screw (2.3%) and rod fracture (14.1%) rates similar between groups but trended toward less occurrence with S2AI (OR 0.47, P= 0.06). Revision surgery occurred in 22.7%, and in 8.5% for iliac fixation specifically, but with no differences between fixation types (P = 0.55 and P = 0.365). Pelvic fixation failure conferred worse HRQL scores (physical component score [PCS] 36.23 vs. 39.37, P= 0.04; ODI 33.81 vs. 27.93, P = 0.036), and less 2 years improvement (PCS 7.69 vs. 10.46, P = 0.028; SRS 0.83 vs. 1.03, P = 0.019; ODI 12.91 vs. 19.77, P = 0.0016). Lumbopelvic fixation failure rates were high following ASD correction, and associated with lesser clinical improvements. S2AI screws were more likely to demonstrate loosening, but less commonly associated with rod fractures at the lumbopelvic region.

Biomechanical study of rod stress in lumbopelvic fixation with lateral interbody fusion: an in vitro experimental study using synthetic bone models.

Despite improvements in surgical techniques and instruments, high rates of rod fracture following a long spinal fusion in the treatment of adult spinal deformity (ASD) remain a concern. Thus, an improved understanding of rod fracture may be valuable for better surgical planning. The authors aimed to investigate mechanical stress on posterior rods in lumbopelvic fixation for the treatment of ASD. Synthetic lumbopelvic bone models were instrumented with intervertebral cages, pedicle screws, S2-alar-iliac screws, and rods. The construct was then placed in a testing device, and compressive loads were applied. Subsequently, the strain on the rods was measured using strain gauges on the dorsal aspect of each rod. When the models were instrumented using titanium alloy rods at 30° lumbar lordosis and with lateral interbody fusion cages, posterior rod strain was highest at the lowest segment (L5-S1) and significantly higher than that at the upper segment (L2-3) (p = 0.002). Changing the rod contour from 30° to 50° caused a 36% increase in strain at L5-S1 (p = 0.009). Changing the rod material from titanium alloy to cobalt-chromium caused a 140% increase in strain at L2-3 (p = 0.009) and a 28% decrease in strain at L5-S1 (p = 0.016). The rod strain at L5-S1 using a flat bender for contouring was 23% less than that obtained using a French bender (p = 0.016). In lumbopelvic fixation in which currently available surgical techniques for ASD are used, the posterior rod strain was highest at the lumbosacral junction, and depended on the contour and material of the rods.

Sacral Insufficiency Fractures.

Primary osteoporosis is the most common cause of sacral insufficiency fractures (SIFs). Therefore, a multidisciplinary team approach is necessary for treatment of the fracture and the underlying biologic pathology, as well as prevention of future fragility fractures. The presentation of SIFs typically includes lower back or buttock pain after a ground-level fall or without an identified trauma. Symptoms often have an insidious onset and are nonspecific; consequently, a delay in diagnosis and treatment is common. Clinicians need to have a high index of suspicion, particularly in high-risk patients. Postmenopausal women who are >55 years of age are the most common demographic affected by SIFs. Other risk factors include osteoporosis, history of a prior fragility fracture, local irradiation, long-term corticosteroid use, rheumatoid arthritis, metabolic bone disorders, vitamin D deficiency, pregnancy, history of prior multilevel spinal fusion, and malignancy. Typical imaging on computed tomography (CT) shows sclerosis of cancellous bone in the sacral ala, with or without a discrete fracture line or displacement. Magnetic resonance imaging is more sensitive than CT and shows hypointense signal on T1-weighted sequences and hyperintensity on T2-weighted or short tau inversion recovery sequences. The treatment of SIFs is dependent on the severity of symptoms, fracture displacement, and instability of the pelvis. Accepted treatments include nonoperative rehabilitation, sacroplasty, iliosacral screw fixation, transsacral bar or screw fixation, transiliac internal fixation, and lumbopelvic fixation.

Management of a rare case of isolated U-shaped displaced sacral fracture in a young female high school student

Sacral fractures in young healthy patients are usually linked to high-energy trauma. They are often associated with multiple other injuries. Isolated sacral fractures are rare and can be easily missed in the absence of other surrounding pelvic or spinal injuries. In this article, we present a rare case of isolated U-shaped displaced sacral fracture despite the high-energy mechanism of injury being missed on initial presentation. This is a 17-year-old healthy female who presented to the emergency department after falling from five-meter height. She complained of lower back pain and inability to ambulate. Physical examination revealed significant sacral tenderness, bilateral lower limb weakness and hypoesthesia, anesthesia of the saddle area, weak anal tone and absent anal reflex. Initial radiographs showed no apparent fractures. Further imaging by pelvic computed tomography, however, revealed an isolated U-shaped displaced sacral fracture. The patient was treated by decompression and lumbopelvic fixation by triangular osteosynthesis and iliosacral screw. This fixation method restored stability of the spinopelvic junction and allowed for early mobilization. At her 18-month follow-up visit, she showed minimal disability score (10%) on the Oswestry Disability Index. In conclusion, sacral fractures are considered exceedingly rare to occur in isolation and in young healthy patients.

Modified Lumbopelvic Technique Using S1 Pedicle Screws for Spinopelvic Dissociation U-Type and H-Type Sacral Fractures With Kyphotic Deformity.

Spinopelvic dissociation injuries are complex injuries defined as discontinuity between the appendicular and axial skeleton. Fracture patterns are variable, but U-type and H-type fractures are common and often present with kyphotic deformity along with translational displacement and impaction. The ideal method of fixation has not been established for these injuries. The goals of treatment include restoration of alignment, stability, and neural decompression as needed. Traditional methods of lumbopelvic fixation have spanned the upper sacral fracture site. Our novel modified method of lumbopelvic fixation directly instruments the S1 body. This allows for direct manipulation of the fracture which we theorize improves reduction and increases stability across the fracture. This article characterizes the injury patterns, outlines the modified technique, and reports the clinical and radiographic outcomes of our modified lumbopelvic fixation technique and construct.

Biomechanical investigation of S2 alar-iliac screw and S1 pedicle screw fixation in the treatment of Denis type II sacral fractures.

Although S2 alar-iliac screw technique has been widely used in spinal surgery, its applicability to pelvic fractures is largely unknown. This study aimed to evaluate the biomechanical stability of S2 alar-iliac screw and S1 pedicle screw fixation in the treatment of Denis II sacral fractures. Twenty-eight artificial pelvic fracture models were treated with unilateral lumbopelvic fixation, sacroiliac screw fixation, S2 alar-iliac screw and S1 pedicle screw fixation, and S2 alar-iliac screw and contralateral S1 pedicle screw fixation (Groups 1-4, respectively; N = 7 per group). Each model was cyclically tested under increasing axial compression. Optical motion-tracking was used to assess relative displacement and gap angle, and the number of failure cycles. Relative displacement was significantly smaller in Group 3 than in Groups 1 (p = 0.004) and 4 (p < 0.001) but not significantly different between Groups 3 and 2 (p = 0.290). The gap angle in Group 3 was significantly smaller than that in Group 1 (p = 0.009) on the sagittal plane but significantly larger than that in Group 4 (p = 0.006) on the horizontal plane. A number of failure cycles was significantly higher in Group 3 than in Groups 1 (p = 0.002) and 4 (p = 0.004) but not significantly different between Groups 3 and 2 (p = 0.910). From a biomechanical perspective, S2 alar-iliac screw and S1 pedicle screw fixation can provide good stability in the treatment of Denis II sacral fractures.

Surgical strategy of lumbopelvic instrumentation in the treatment of lumbosacral tuberculosis: S2-alar-iliac screws vs iliac screws.

The objective of this study was to evaluate the feasibility and clinical outcomes of S2-alar-iliac (S2AI) and iliac screw (IS) techniques in the lumbopelvic reconstruction of lumbosacral tuberculosis patients. From January 2014 to August 2016, 26 patients with lumbosacral tuberculosis attending the 8th Medical Centre of Chinese PLA General Hospital were included in this retrospective study. The subjects were divided into two groups based on the lumbopelvic fixation type (16 patients in the S2AI group, 10 patients in the IS group). The operation time, blood loss, length of hospitalisation, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, visual analogue scale (VAS), Oswestry Disability Index (ODI), ambulatory status, and 36-Item Short-Form Health Survey (SF-36) scores of the patients in two groups were recorded and compared. In addition, surgical complications were collected and analysed. The operation time and intraoperative blood loss were significantly lower in the S2AI group than that in the IS group (P < .05). Compared with preoperative data, postoperative data showed significant improvement in ESR, CRP level, ODI scores, VAS scores, ambulatory status, and SF-36 (P < .05), but there was no significant difference in remission degree between the two groups. Compared with IS group, The S2AI group had significantly lower rates of symptomatic screw prominence (P < .05). Both the IS and S2AI fixation techniques can achieve satisfactory outcomes for the restoration of lumbosacral stability of lumbosacral tuberculosis. Furthermore, compared to the traditional IS fixation technique, the S2AI fixation technique can shorten operation time and reduce surgical trauma for the treatment of lumbosacral tuberculosis.

Lumbopelvic fixation with S2 alar-iliac screws for U-shaped sacral fractures

ObjectiveTo investigate the surgical methods and clinical effects of lumbopelvic fixation (LPF) with S2 alar-iliac (S2AI) screws for U-shaped sacral fractures. MethodsFrom December 2019 to August 2020, 14 patients with U-shaped sacral fractures were treated with LPF using S2AI screws. Demographics, fracture classification, mechanism of injury, surgical treatment, complications and clinical results were assessed. All patients had a LPF with or without nerve decompression. The reduction quality was evaluated according to the Matta criteria. Neurological function was evaluated according to the Gibbons grading. The activities of daily life were evaluated according to the Majeed scoring system at the last follow-up. ResultsAmong 14 consecutive patients with U-shaped sacral fractures, the age at injury ranged from 13 to 72 years (average 30.3 ± 17.5 years). There were 4 males and 10 females. All patients were followed up for 6–15 months (average 7.8 ± 2.7 months). Thirteen patients were fixed with bilateral S2AI screws, and one patient was fixed only unilaterally due to unilateral spinopelvic dissociation. The excellent and good rate of postoperative pelvic reduction quality was 92% (excellent 10, good 3, fair 1). At the latest follow-up, the excellent and good rate of pelvic function was 100% (excellent 9, good 5) and all patients achieved different extents of neurological recovery. One patient had a postoperative superficial surgical site infection, which healed after debridement. Radiological examination at 3–6 months after operation showed that all fractures had healed. No complications were found in any patients during follow-up, such as implant fracture, loss of reduction, deep wound infection, wound dehiscence and screw protrusion discomfort. ConclusionLPF with S2AI screws for the treatment of U-shaped sacral fractures has exhibited distinct advantages, including firm fixation, a low rate of surgical site complications and satisfactory clinical efficacy. This approach provides sufficient stability to accelerate the commencement of postoperative rehabilitation.

Abstract #24 Lumbopelvic Fixation for Sacral Fractures with Spinopelvic Dissociation: Clinical Experience in Two Trauma Centers in Medellín, Colombia, and Literature Review

Abstract #24 Lumbopelvic Fixation for Sacral Fractures with Spinopelvic Dissociation: Clinical Experience in Two Trauma Centers in Medellín, Colombia, and Literature Review

A novel anatomo-physiologic high-grade spondylolisthesis model to evaluate L5 nerve stretch injury after spondylolisthesis reduction

L5 nerve palsy is a well-known complication following reduction of high-grade spondylolisthesis. While several mechanisms for its occurrence have been proposed, the hypothesis of L5 nerve root strain or displacement secondary to mechanical reduction remains poorly studied. The aim of this cadaveric study is to determine changes in morphologic parameters of the L5 nerve root during simulated intraoperative reduction of high-grade spondylolisthesis. A standard posterior approach to the lumbosacral junction was performed in eight fresh-frozen cadavers with lumbosacral or lumbopelvic screw fixation. Wide decompressions of the spinal canal and L5 nerve roots with complete facetectomies were accomplished with full exposure of the L5 nerve roots. A 100% translational slip was provoked by release of the iliolumbar ligaments and cutting the disc with the attached anterior longitudinal ligament. To evaluate the path of the L5 nerves during reduction maneuvers, metal bars were inserted bilaterally at the inferomedial aspects of the L5 pedicle at a distance of 10 mm from the midpoint of the L5 pedicle screws. There was no measurable change in length of the L5 nerve roots after 50% and 100% reduction of spondylolisthesis. Mechanical strain or displacement during reduction is an unlikely cause of L5 nerve root injury. Further anatomical or physiological studies are necessary to explore alternative mechanisms of L5 nerve palsy in the setting of high-grade spondylolisthesis correction, and surgeons should favor extensive surgical decompression of the L5 nerve roots when feasible.

Risk Factors for Proximal Junctional Kyphosis in Fusions from the Sacrum to L1 or L2 for Adult Spinal Deformity.

Introduction Several targets have been proposed to achieve satisfactory alignment and favorable outcomes in adult spinal deformity surgery. Stopping the upper instrumented vertebra (UIV) at the thoracolumbar junction levels, especially between T11 and L1, is considered a high-risk factor for the development of proximal junctional kyphosis (PJK). Nevertheless, it is unknown in which patients the results of surgery are satisfactory when L1 or L2 is set as UIV with lumbosacral fixation. This study aimed to identify the risk factors for PJK in patients with lumbosacral fixation with L1 or L2 as UIV. Methods From January 2011 to December 2019, 21 consecutive patients who underwent lumbopelvic fixation for adult spinal deformity were included. The patients were divided into two groups: the PJK group (n=7) and the nonPJK group (n=14). Patients who experienced PJK within half a year of surgery were included in the PJK group. Pelvic incidence (PI), lumbar lordosis (LL), pelvic tilt (PT), thoracic kyphosis (TK), thoracic compensation (TK compensation), sagittal vertical axis (SVA), T10-L2 angle, and T1 pelvic angle (TPA) were measured before and after surgery. Results No difference was found between the two groups in terms of age and sex at the time of surgery. The indices that were significantly different between the two groups were preoperative PT, PI minus LL, TK, TPA, TK compensation, and postoperative T10-L2 angle. No significant differences were found in postoperative LL, PI minus LL, PT, TK, TPA, or SVA. Conclusions Preoperative X-ray indices, including preoperative TPA, TK compensation, TK, PT, and PI-LL, determined the risk of PJK in fusions from the sacrum to L1 or L2. Appropriate patient selection is crucial for the success of this surgery.

S2-Alar-Iliac Screw Fixation versus Iliac Screw Fixation in the Treatment of Sacral Fractures

Purpose To compare the short-term therapeutic effects of S2-alar-iliac (S2AI) screw fixation and iliac screw fixation techniques in managing sacral fractures. Methods From September 2015 to May 2020, 42 patients with sacral fractures who underwent lumbopelvic fixation by a single surgeon were analyzed. The patients were divided into the S2AI screw group (19 patients) and the iliac screw group (23 patients). Operative data, reduction quality, postoperative complications, and functional outcomes were evaluated. Results The incidence of unplanned reoperation was significantly different between patients treated with S2AI screws than in those treated with iliac screws (0 versus 6, p = 0.02). The mean intraoperative estimated blood loss was 405.26 ± 229.67 mL in the S2AI screw group and 539.13 ± 246.32 mL in the iliac screw group (P = 0.08). No significant difference was observed in either group regarding the quality of reduction, functional outcome, or low back pain. The reduction quality based on the Matta criteria and excellent/good outcomes were 21/2 in the iliac screw group and 17/2 in the S2AI screw group. The functional outcomes based on the Majeed score and excellent/good/fair outcomes were 17/3/3 in the iliac screw group and 17/1/1 in the S2AI screw group. No complications, including implant breakage, loosening of the implant, or loss of reduction were found in either group during follow-up. Conclusion Both S2AI screws and iliac screws were effective in the treatment of sacral fractures. The use of S2AI screws, however, was independently associated with fewer unplanned reoperations for surgical site infection, wound dehiscence, and symptoms of screw protrusion than the use of iliac screws.

Letter: Sacroplasty Augmentation of Instrumented Pelvic Reconstruction After High Sacrectomy: A Technical Case Report.

Letter: Sacroplasty Augmentation of Instrumented Pelvic Reconstruction After High Sacrectomy: A Technical Case Report.