Intraoperative fat embolism syndrome associated with implantation of titanium sacroiliac joint fusion implants: a report of two cases.

Background: For patients undergoing long-construct fusion surgeries, simultaneous sacroiliac joint (SIJ) fusion is a growing trend in spine surgery. Some options for posterior SIJ fusion include 3D-printed triangular titanium implants or self-harvesting SIJ screws. Both implants require fixation within the sacrum and ileum. Fat embolism syndrome is a rare but known complication of lumbar pedicle instrumentation but has never been reported in association with SIJ fusion, regardless of implant type. We report the first two known cases of fat embolism associated with placement of SIJ fusion devices during long construct posterior spine fusion. Case Description: Case 1-a 50-year-old female with multiple previous spine surgeries complicated by osteomyelitis/diskitis that was successfully eradicated, underwent T10-pelvis posterior spinal fusion (PSF), L4 pedicle-subtracting-osteotomy, and bilateral SIJ fusion. During implantation of each SIJ fusion device, the patient's hemodynamic status deteriorated necessitating vasopressor support, intravenous fluid bolus, and hyperventilation, but quickly resolved. The case was completed without further issue, and she had an uneventful post-operative course. Case 2-a 71-year-old female with a past medical history of ankylosing spondylitis, previous L2-L5 PSF, rheumatoid arthritis on chronic steroids, underwent a T9-pelvis PSF, bilateral SIJ fusion, L4 pedicle subtraction osteotomy, T10-L1 Smith Peterson osteotomies. After implantation of the second SIJ fusion device, she became hypotensive and tachycardic, pulses were absent, and cardiopulmonary resuscitation was initiated. Pulses returned quickly, the index surgery was terminated, and she was transferred to the intensive care unit (ICU). In the ICU she was quickly weaned off the ventilator on post-operative day 1. On post-operative day 4, the patient returned to the operating room for completion of the surgery and had an extended, but uneventful, recovery afterwards. Conclusions: We report on the first two known cases of fat embolism syndrome occurring immediately after implantation of SIJ fusion devices. Spine surgeons should be aware of this rare, but potentially fatal, complication. Collaboration with the anesthesia team and optimization of the patient's hemodynamic status prior to implantation may help prevent catastrophic complications.

Atypical Mycobacterial Infections of the Spine: Evaluation and Management.

BACKGROUND: Atypical mycobacterial infections of the spine can be difficult to treat and represent a subset of the vertebral osteomyelitis and diskitis spectrum often requiring early and aggressive surgical intervention. The purpose of this review is to improve the understanding of and approach to disease management from the perspective of the spine surgeon. MATERIALS AND METHODS: Debridement or excision of the affected levels may be necessary to decrease mycobacterial loads and restore biomechanics. A close relationship with the patient's internal medicine and infectious disease specialists should be maintained to ensure disease eradication or remission. Long-term suppressive antibiotic therapy may be required for infection control. RESULTS AND CONCLUSION: Atypical mycobacterial spine infections are rare, complex, and difficult to eradicate. Our institution proposes a collaborative effort among the spine surgeon, infectious disease specialists, and internal medicine specialists to best approach the work-up, diagnosis, and treatment of these infections. [Orthopedics. 2024;47(2):e61-e66.].

Genetics of Intervertebral Disc Degeneration.

PURPOSE OF REVIEW: Intervertebral disc degeneration is a contributor to chronic back pain. While a part of the natural aging process, early or rapid intervertebral disc degeneration is highly heritable. In this review, we summarize recent progress towards unraveling the genetics associated with this degenerative process. RECENT FINDINGS: Use of large cohorts of patient data to conduct genome-wide association studies (GWAS) for intervertebral disc disease, and to lesser extent for aspects of this process, such as disc height, has resulted in a large increase in our understanding of the genetic etiology. Genetic correlation suggests that intervertebral disc disease is pleiotropic with risk factors for other diseases such as osteoporosis. The use of Mendelian Randomization is slowly establishing what are the causal relationships between intervertebral disc disease and factors previously correlated with this disease. The results from these human genetic studies highlight the complex nature of this disease and have the potential to lead to improved clinical management of intervertebral disc disease. Much additional work should now be focused on characterizing the causative relationship various co-morbid conditions have with intervertebral disc degeneration and on finding interventions to slow or halt this disease.

Alternative Uses of O-Arm and Stealth Navigation Technology Over 10 Years: The University of Colorado Experience.

Intraoperative computed tomography scanning with O-arm and use of Stealth navigation can improve surgical outcomes in a variety of orthopedic subspecialties. In spine surgery, the accuracy, precision, and safety of pedicle screw and interbody implant placement has improved. This technology is now routinely used in percutaneous pedicle screw placement and minimally invasive sacroiliac joint fusion. Other applications include, but are not limited to, isthmic pars defect repair, lumbosacral pseudoarticulation resection in Bertolotti's syndrome, radiofrequency ablation, and en bloc tumor resection. Intraoperative navigation has numerous applications, and use of this technology should continue to evolve as the technology advances. [Orthopedics. 2023;46(2):e89-e97.].

Catastrophic acute failure of pelvic fixation in adult spinal deformity requiring revision surgery: a multicenter review of incidence, failure mechanisms, and risk factors.

OBJECTIVE: There are few prior reports of acute pelvic instrumentation failure in spinal deformity surgery. The objective of this study was to determine if a previously identified mechanism and rate of pelvic fixation failure were present across multiple institutions, and to determine risk factors for these types of failures. METHODS: Thirteen academic medical centers performed a retrospective review of 18 months of consecutive adult spinal fusions extending 3 or more levels, which included new pelvic screws at the time of surgery. Acute pelvic fixation failure was defined as occurring within 6 months of the index surgery and requiring surgical revision. RESULTS: Failure occurred in 37 (5%) of 779 cases and consisted of either slippage of the rods or displacement of the set screws from the screw tulip head (17 cases), screw shaft fracture (9 cases), screw loosening (9 cases), and/or resultant kyphotic fracture of the sacrum (6 cases). Revision strategies involved new pelvic fixation and/or multiple rod constructs. Six patients (16%) who underwent revision with fewer than 4 rods to the pelvis sustained a second acute failure, but no secondary failures occurred when at least 4 rods were used. In the univariate analysis, the magnitude of surgical correction was higher in the failure cohort (higher preoperative T1-pelvic angle [T1PA], presence of a 3-column osteotomy; p < 0.05). Uncorrected postoperative deformity increased failure risk (pelvic incidence-lumbar lordosis mismatch > 10°, higher postoperative T1PA; p < 0.05). Use of pelvic screws less than 8.5 mm in diameter also increased the likelihood of failure (p < 0.05). In the multivariate analysis, a larger preoperative global deformity as measured by T1PA was associated with failure, male patients were more likely to experience failure than female patients, and there was a strong association with implant manufacturer (p < 0.05). Anterior column support with an L5-S1 interbody fusion was protective against failure (p < 0.05). CONCLUSIONS: Acute catastrophic failures involved large-magnitude surgical corrections and likely resulted from high mechanical strain on the pelvic instrumentation. Patients with large corrections may benefit from anterior structural support placed at the most caudal motion segment and multiple rods connecting to more than 2 pelvic fixation points. If failure occurs, salvage with a minimum of 4 rods and 4 pelvic fixation points can be successful.

Multidisciplinary Treatment of Persistent Nontuberculous Mycobacterial Spinal Hardware Infection with a Pedicled Superior Gluteal Artery Perforator Flap.

Nontuberculous mycobacterial hardware infections are extremely challenging to treat. Multidisciplinary care involving removal of infected hardware, thorough debridement, and durable soft tissue coverage in conjunction with antibiotic therapy is essential for successful management. This case report presents a patient with chronic mycobacterial spinal hardware infection that underwent successful treatment with aggressive serial debridements and reconstruction with a large pedicled superior gluteal artery perforator flap coverage.

Blockade of Osteoclast-Mediated Bone Resorption With a RANKL-Inhibitor Enhances Bone Formation in a Rat Spinal Fusion Model.

STUDY DESIGN: Rat spine fusion model. OBJECTIVE: The present study aimed to determine whether administration of osteoprotegerin (OPG) in a rat model of spinal fusion increases bone volume, bone density, and decreases osteoclasts in the fusion mass. SUMMARY OF BACKGROUND DATA: OPG is a soluble RANK-ligand inhibitor that blocks osteoclast differentiation and activation. This makes it a potential agent to control the remodeling process and enhance bone mass during spinal fusion. MATERIALS AND METHODS: Forty-eight male Sprague-Dawley rats received a one-level spinal fusion of L4-L5 with bone allograft. Rats were then divided into four groups according to initiation of treatment: (1) saline on day 0 (saline), (2) OPG on day 0 (OPG D0), (3) OPG on day 10 (OPG D10), and (4) OPG on day 21 (OPG D21) postsurgery. After their initial injection, rats received weekly subcutaneous injections of OPG (10 mg/kg) and were euthanized six weeks postsurgery. MicroCT analysis of the fusion site and histological analysis of bone surface for quantification of osteoclast lining was performed. RESULTS: Increased bone volume in the fusion site and around the spinous process was seen in OPG D0 and OPG D10 when compared with saline. Mean trabecular thickness was greater in all groups receiving OPG compared with saline, with OPG D0 and OPG D10 having significantly greater mean trabecular thickness than OPG D21. All OPG groups had less bone surface lined with osteoclasts when compared with Saline, with OPG D0 and OPG D10 having fewer than OPG D21. CONCLUSIONS: This study indicates that OPG inhibited osteoclast bone resorption, which led to greater bone at the fusion site. Future studies investigating OPG on its own or in combination with an osteogenic factor to improve spinal fusion outcomes are warranted to further elucidate its potential therapeutic effect.

Pre-Operative Planning in Complex Deformities and Use of Patient-Specific UNiD™ Instrumentation.

STUDY DESIGN: Review of current literature and authors experience. OBJECTIVE: Pre-operative planning is an integral part of complex spine surgery. With the advent of computer-assisted planning, multiple surgical plans can be evaluated utilizing alignment parameters, and the best plan for individual patients selected. However, the ability to evaluate and measure surgical correction goals intraoperatively are still limited. The use of patient-specific UNiD rods, created based on pre-operative plans, provided an initial tool for implementation of pre-operative plans in the operative setting. METHODS: A literature review for the use of patient-specific UNiD rods in thoracolumbar spine complex surgery was performed. The articles were selected and reviewed for the initial experience/outcomes of these techniques. Further, the initial experience of the authors at The University of Colorado is described. RESULTS: The use of UNiD patient-specific rods, in combination with pre-operative planning has been shown to provide a higher rate of patients with spinopelvic alignment parameters within currently accepted ranges. This includes improvement of sagittal vertical axis (SVA) < 50 mm and pelvic incidence (PI)-lumbar lordosis (LL) = ± 10°. Multiple authors have shown improvement in pelvic tilt to age adjusted values but note continued difficulties in obtaining correction goals. CONCLUSIONS: The use of pre-operative planning software and UNiD patient-specific rods has been shown to improve surgeon's ability to achieve spinopelvic alignment parameters, specifically SVA and PI-LL, along with other possible benefits. Further research is needed regarding long-term value of the technology.

Navigation Options for Spinal Surgeons: State of the Art 2021.

The use of navigation in spinal surgery has been increasing over the past decade. There are three primary types of navigation in spinal surgery: three-dimensional image-based computer-assisted navigation, robot-assisted navigation, and three-dimensional printed patient-specific drill guides for navigation. All three have demonstrated increased accuracy in placement of spinal instrumentation versus freehand or fluoroscopic-assisted techniques. Each has unique preoperative and intraoperative technical considerations. All three typically rely on three-dimensional imaging and will have varied radiation exposure to the patient and surgical staff based on specific imaging settings used. Navigation options are continually improving and are expected to broaden efficiency, accuracy, and indications in the future.

Laser Marking of Spine Rods Is Strongly Associated With Risk of Clinical Rod Failure.

INTRODUCTION: What is overlooked in clinical studies are the possibilities of manufacturing and design aspects of the instrumentation that could initiate rod fracture. Although revision because of hardware fracture is a small fraction of the overall revision rates (12.1% to 13.7%), there are sufficient numbers of revision cases where hardware removed can undergo a thorough metallurgic analysis. This study is unique in that rod characteristics, such as alloy, surface markings, and fracture type, seen at fracture surfaces are considered in the analysis. METHODS: This work was conducted under both a retrospective and prospective IRB. Patients considered for this study were between the ages of 18 and 85 years who underwent or were undergoing revision spine surgery with previous instrumentation in the cervical, thoracic, or lumbar region and evidence of at least one of the following: catastrophic hardware failure, pseudarthrosis, implant loosening, or nonfusion. Inclusion criteria were determined through radiographic and medical records review. RESULTS: Fifty-six patients who had revision procedures because of different indications were included; 101 rods were removed, tested for fracture, and included in the analysis. Laser marking is significantly (P < 0.0001) associated with rod fracture. Detailed analysis showed notable surface and subsurface changes as the result of the marking, such as surface melting, cracking, and notching, creating locations to initiate a fracture. The three most informative variables to clinical rod fracture using multiple regression modeling were body mass index, presence or absence of laser mark (yes/no), and length of posterior fusion (≤2 spinal levels/>2 spinal levels). It was found that the relative risk of rod fracture is 23 times higher during 20 postoperative years than in cases with this index <0.4. DISCUSSION: For a patient with a given body mass index, if they require a multilevel fixation greater than two levels and rods with laser marks are used, the risk of early rod fracture increases by 40%.

Estrogen receptor Alpha in human knee articular cartilage of healthy and osteoarthritic females.

OBJECTIVE: Estrogen and osteoarthritis association has previously been proposed. This study evaluates the presence of estrogen receptors (ER)-α in articular cartilage, and its association. METHODS: A prospective cohort study of women undergoing anterior cruciate ligament reconstruction (controls) or total knee arthroplasty (cases) was performed. Cartilage samples were processed and ER-α expression was quantified. RESULTS: Twenty patients were included: 12 cases and 8 controls. ER-α expression was higher in the case subjects. CONCLUSION: Increased ER-α expression is associated with age, and degeneration. This suggests estrogen deficiency is a risk for osteoarthritis and is inversely related to proliferative looking chondrocytes.

Expectoration of anterior cervical discectomy and fusion cage: a case report.

Anterior cervical implant failure can lead to catastrophic sequalae and requires prompt evaluation and management to reduce significant morbidity. This case report describes a 51-year-old female who underwent a C2-3 and C3-4 anterior cervical discectomy and fusion (ACDF) with stand-alone, integrated plate-cage interbody devices for cervical spondylotic myelopathy (CSM). Initial procedure was performed at an outside institution. Unfortunately, no radiographic follow up was obtained by the primary surgeon during the initial post-operative period. Post-operatively she experienced persistent dysphagia and troubles swallowing. The patient was eventually seen by the ear, nose and throat (ENT) service at our institution. Eighteen months after the index procedure, a nasolaryngoscopy revealed exposure of her ACDF implant through the posterior aspect of her pharynx. The ENT service obtained radiographs and immediately contacted our Spine Surgery service. Repeat anterior approach with implant removal was planned; however, during the interim, the patient suffered a coughing fit and complete expectoration of the C2-3 implant with the locking screws in place had occurred. Patient experienced immediate relief of symptoms. Miraculously, the patient did not develop airway compromise, infection, or return of severe dysphagia symptoms. During continued follow up, no significant clinical sequelae of her anterior cervical soft tissue structures were identified. The patient chose to decline further surgical management of her cervical spine. This case report highlights a potentially catastrophic complication following ACDF. Several modifiable factors including implant design, C2-3 ACDF cage placement, use of post-operative radiographs, and patient education regarding need for consistent follow up may have prevented this complication. Implant extrusion is a rare, but potentially serious complication following ACDF. Presenting symptoms can be generalized and mild including pain, swelling, or worsening dysphagia. It is paramount to obtain orthogonal X-rays for routine follow-up of post-surgical ACDF patients, especially if dysphagia persists or worsens. Immediate surgical management in recommended if significant post-operative cage migration is encountered.

Postoperative pelvic incidence (PI) change may impact sagittal spinopelvic alignment (SSA) after instrumented surgical correction of adult spine deformity (ASD).

OBJECTIVES: To study factors causing postoperative change of PI after surgical correction of ASD and to assess the effect of this variability on postoperative PI-LL mismatch. BACKGROUND: PI is used as an individual constant to define lumbar lordosis (LL) correction goal (PI-LL < 10). Postoperative changes of PI were shown but with opposite vectors. The impact of the PI variability on the postoperative PI-LL has not been studied. METHODS: The medical and radiographic data analyzed for patients who underwent long posterior instrumented spinal fusion. Inclusion criteria are age, ≥ 20 years old; ASD due to degenerative disk disease (DDD) or scoliosis (DS); ≥ 3 levels fused; and 2-year follow-up or revision. Studied parameters are LL (L1-S1), PI, sacral slope (SS), pelvic tilt (PT), and PI-LL. Measurement error and postoperative changes were defined. Statistical analysis includes ANOVA, correlation, regression, and risk assessment by odds ratio; P ≤ 0.05 considered statistically significant. RESULTS: Eighty patients were included: mean age, 62.4 years-old (SD, 11.1); female, 63.7%; mean body mass index (BMI), 27.1 (SD, 5.6). Distribution of patients by follow-ups includes preoperative 100%; postoperative (1-3 weeks), 100%; 11-13 months. 90%; 22-26 months, 58%; and revision: 24%. Pre- versus postoperative PI (∆PI) changed both positively and negatively and the absolute value of change|∆PI| exceeded measurement error (P ≤ 0.05) reaching as high as 31°, and progressed with time; R2 dropped from 0.73 to 0.45 (P < 0.001); ∆PI depended on disproportional changes of SS and PT, preoperative PI, and change of LL. Obesity, DS, and absence of sacroiliac fixation increased |∆PI|. The risk of LL insufficient correction (PI-LL > 10°) associated with a |∆PI|> 6°, P = 0.05. Sacroiliac fixation diminished PI variability only during the first postoperative year. CONCLUSION: Preoperative variability and postoperative instability of PI diminish the applicability of the PI-LL < 10° goal to plan correction of LL. An alternative method is offered. LEVEL OF EVIDENCE: IV.

Toxicology Screening Testing in Patients Undergoing Spine Surgery: A Prospective Observational Pilot Study.

BACKGROUND: Chronic opioid use and polypharmacy are commonly seen in chronic pain patients presenting for spine procedures. Substance abuse and misuse have also been reported in this patient population. Negative perioperative effects have been found in patients exposed to chronic opioid, alcohol, and recreational substances. Toxicology screening testing (TST) in the perioperative period provides useful information for adequate preoperative optimization and perioperative planning. METHODS: We designed a pilot study to understand this population's preoperative habits including accuracy of self-report and TST-detected prescribed and unprescribed medications and recreational substances. We compared the results of the TST to the self-reported medications using Spearman correlations. RESULTS: Inconsistencies between TST and self-report were found in 88% of patients. Spearman correlation was 0.509 between polypharmacy and intraoperative propofol use, suggesting that propofol requirement increased as the number of substances used increased. CONCLUSIONS: TST in patients presenting for spine surgery is a useful tool to detect substances taken by patients because self-report is often inaccurate. Discrepancies decrease the opportunity for preoperative optimization and adequate perioperative preparation.

Strap stabilization for proximal junctional kyphosis prevention in instrumented posterior spinal fusion.

STUDY DESIGN: This is a retrospective, single-institution, cohort study. OBJECTIVES: To evaluate the association of Mersilene tape use and risk of proximal junctional kyphosis (PJK), after surgical correction of adult spinal deformity (ASD) by posterior instrumented fusion (PIF). PJK, following long spinal PIF, is a complication which often requires reoperation. Mersilene tape, strap stabilization of the supra-adjacent level to upper instrumented vertebra (UIV) seems a preventive measure. METHODS: Patients who underwent PIF for ASD with Mersilene tape stabilization (case group) or without (control group) between 2006 and 2016 were analyzed preoperatively to 2-year follow-up. Matching of potential controls to each case was performed. Radiographic sagittal Cobb angle (SCA), lumbar lordosis, pelvic tilt, sacral slope, and pelvic incidence were measured pre- and postoperatively, using a deformity measuring software program. PJK was defined as progression of postoperative junctional SCA at UIV ≥ 10°. RESULTS: Eighty patients were included: 20 cases and 60 controls. The cumulative rate of PJK ≥ 10° at 2-year follow-up was 15% in cases versus 38% of controls (OR = 0.28; P = 0.04) with higher latent period in cases, (20 vs. 7.5 months), P = 0.018. Mersilene tape decreased risk of PJK linked with the impact of the following confounders: age, ≥ 55 years old (OR = 0.19; 0.02 ≥ P ≤ 0.03); number of spinal levels fused 7-15 (OR = 0.13; 0.02 ≥ P ≤ 0.06); thoracic UIV (T12-T1) (OR = 0.13; 0.02 ≥ P ≤ 0.06); BMI ≥ 27 kg/m2 (OR = 0.22; 0.03 ≥ P ≤ 0.08); and osteoporosis (OR = 0.13; 0.02 ≥ P ≤ 0.08). CONCLUSIONS: Mersilene tape at UIV + 1 level decreases the risk of PJK following PIF for ASD. These slides can be retrieved under Electronic Supplementary Material.

Radius of Curvature in Patient-Specific Short Rod Constructs Versus Standard Pre-Bent Rods.

BACKGROUND: Recent studies support the need for sagittal alignment restoration when performing lumbar degenerative spinal fusions. The development of patient-specific spine rods (PSSRs) may help maintain or improve sagittal alignment in these surgeries. METHODS: A retrospective review was conducted for patients who underwent posterior spinal surgeries involving 4 or less levels. The preplanned PSSR radii of curvature (ROC) was compared with standard prebent rods with a ROC of 125 mm. All surgeries were performed at a single institution by 3 surgeons from September 2016 through October 2018. Data were then compared using a 2-tailed paired t test. PSSR had either 1 or 2 definitive ROCs. RESULTS: For rods with 2 ROCs, the "cranial" curve was measured between the upper instrumented level and L4 or L5. The "caudal" curve was measured between L4 or L5 and the lower instrumented level. The PSSR with 1 ROC and the caudal portion of the rods with 2 ROCs were significantly smaller than the industry standard ROC. CONCLUSIONS: PSSR demonstrate more acute ROC than industry standard rods. In PSRs, the most lordosis occurs between L4-S1 and flattens out at the thoracolumbar junction, mimicking the normal distribution of lumbar lordosis. PSSRs could help achieve or maintain sagittal alignment and prevent the sequela of flat back syndrome.

Long-Term Treatment Effect and Predictability of Spinopelvic Alignment After Surgical Correction of Adult Spine Deformity With Patient-Specific Spine Rods.

STUDY DESIGN: Retrospective case series. OBJECTIVE: To evaluate the short- and long-term treatment effect (TE) of spinopelvic parameters after surgical correction of adult spine deformity (ASD) utilizing preoperative planning and patient-specific spine rods (PSSRs), and to assess the correspondence between planned and real outcomes. SUMMARY OF BACKGROUND DATA: PSSR have been used in ASD correction for the last decade. However, a TE and predictability of spinopelvic alignment at long-term follow-up has not been studied. METHODS: Inclusion criteria: male or female; age more than 20 years; correction of ASD with PSSR; 24-month follow-up (or revision surgery). Studied parameters: sagittal vertical axis; lumbar lordosis (LL); pelvic tilt (PT); sacral slope; pelvic incidence (PI); and PI-LL. The measurement error, TE (the differences between postoperative and preoperative values), standardized TE, and predictability of the studied parameters assessed. The variables included categorical (optimal/nonoptimal) and continuous obtained by direct measurements and weighted by individual optimal values. Statistical significance was set at P ≤ 0.05. RESULTS: Thirty-four patients were included: 56% women; the mean age, 63.4 (standard deviation, 12.7); at each follow-up: 32 at 1 to 3 months, 34 at 11 to 13, and 14 at 23 to 25 with 9 followed to the revision surgery. Strong or moderate TE was shown for sagittal vertical axis, LL, and PI-LL. The TE of PT and sacral slope was less significant and lower than planned. PI was not stable in 18%. The changes of continuous variables were more prominent and statistically significant then categorical. The mean values did not show significant differences between planned and postoperative outcomes except for PT. However, the individual deviations were substantial for all parameters. Significant predictability was shown only for LL and PI. CONCLUSION: Use of PSSR showed strong and relatively stable TE in ASD during 2 postoperative years. However, improvement of the planning accuracy may contribute to further enhancement of the method's efficacy. LEVEL OF EVIDENCE: 4.

Transpedicular-Transdiscal Cement Augmentation Treatment of Thoracolumbar Fusion Proximal Junctional Failure.

BACKGROUND: Long instrumented fusions for adult deformity have a proximal junction kyphosis rate between 20% and 40%. When symptomatic, proximal junctional failure (PJF) often requires revision surgery and is associated with significant morbidity. Vertebral cement augmentation (VCA) has been used for prophylaxis against PJF but has not been previously described as treatment after onset of PJF has occurred. We describe a series of patients with PJF of long posterior spinal fusions that were treated at our institution using a novel VCA technique. METHODS: Three patients with PJF above thoracolumbopelvic fusions were retrospectively reviewed following treatment with transpedicular-transdiscal VCA. The medical record was reviewed for demographic data, outcomes scores, and radiographic images. RESULTS: Mean age was 69.3 years. Mean follow-up was 13.3 months. Mean preprocedure visual analog scale score was 8.67, and postprocedure visual analog scale score was 4.00. Mean preprocedure sagittal balance was 9.7 cm, and postprocedure sagittal balance was 5.8 cm. No patients required revision surgery for PJF in the follow-up period. CONCLUSIONS: Transpedicular-transdiscal VCA treatment for PJF is safe and may have the potential to prevent the need for revision surgery. LEVEL OF EVIDENCE: 4.

Mini-open sacroiliac joint fusion with direct bone grafting and minimally invasive fixation using intraoperative navigation.

BACKGROUND: Describe a novel technique for sacroiliac arthrodesis using intraoperative navigation, direct bone grafting, and minimally invasive implants. Report on the outcomes of the first cohort of these patients. METHODS: Institutional review board (IRB) approved, single center, two surgeon, retrospective study. RESULTS: All patients were 18 years or older, primary sacroiliac fusions, and underwent novel technique described. Fifty patients underwent 57 surgeries. Twelve male/38 female patients. All received three sacroiliac implants. Average blood loss 42.8 mL. Average length of stay 1.9 nights. Average follow-up 13.96±13 months. Statistically significant improvements in Visual Analogue Scale (VAS) scores (<0.001) for all time periods 6 weeks, 3 months, 6 months, 12 months compared to preop. Other outcomes scores [Oswestry Disability Index (ODI), and Denver Sacroiliac Joint Questionnaire (DSIJQ)] also showed a general trend for clinical improvement at all postoperative time periods. Of 2/57 (3.5%) complications were identified. No patients required surgical revision within the study window. CONCLUSIONS: Limited open sacroiliac arthrodesis using minimally invasive implants, intraoperative navigation, and direct open bone grafting is safe and demonstrates clinical benefit, similar to other techniques for minimally invasive sacroiliac arthrodesis. There is potential for improved long-term outcomes from increased union rates. KEYWORDS: Sacroiliac dysfunction; minimally invasive sacroiliac fusion; open sacroiliac fusion; navigation.