Clinical differences between periprosthetic and native distal femur fractures: a comparative observational study.

INTRODUCTION: The incidence of periprosthetic distal femur fractures (PDFF) is increasing as the number of total knee replacements becomes more common. This study compared the demographics, fracture characteristics, treatment, and outcomes of periprosthetic versus native distal femur fractures (NDFF). MATERIALS AND METHODS: This was a retrospective cohort study of patients ≥ 18 who underwent surgical fixation of NDFF or PDFF from 2012 to 2020 at a level-1 trauma center. The main variables collected included demographics, AO/OTA fracture classification, fixation construct, concomitant fractures, polytrauma rates, bone density, and reduction quality. Primary outcomes were unexpected return to the operating room (UROR), hospital length of stay, and quality of reduction. T-tests, Fisher's exact tests, and multivariate analyses were used for statistical analysis. RESULTS: 209 patients were identified, including 70 PDFF and 139 NDFF. PDFF patients were elderly females (81%) with isolated (80%) and comminuted (85%) 33 A.3 (71%) fractures. NDFF patients included 53% females, were commonly middle-aged, and displayed comminuted (92%) 33 C.2 fractures. 48% of NDFF patients had concomitant fractures. Intramedullary nailing was the primary fixation for both groups, followed by nail-plate combination (37%) for PDFF and lateral locking plates (21%) for NDFF. NDFF patients experienced significantly longer hospital stays, higher UROR rates, and worse quality of reduction (p < 0.05). PDFF patients had a significantly greater prevalence of low bone density (p < 0.05). CONCLUSION: PDFF occur as isolated injuries with significant metaphyseal comminution in elderly females with low bone quality. NDFF commonly occurs in younger patients with less metaphyseal comminution and concomitant fractures. Intramedullary nailing was the most common treatment for both groups, although preference for nail-plate combination fixation is increasing. NDFF type 33 C fractures are at greater risk of UROR.

Accessory Extensor Pollicis Longus Spanning the Fourth Dorsal Compartment of the Wrist: A Case Report.

Introduction: Variations of the extensor pollicis longus (EPL) tendon of the hand are not uncommon. Yet, this anatomic structure exhibits the least variations among the extensors of the upper extremity. Case Report: This article highlights the presence of an accessory EPL tendon in the fourth dorsal compartment, which was presented as an incidental finding during an elective wrist arthrodesis in a woman in her 40s. Conclusion: Knowledge of this anatomic variation can guide surgical planning and mitigate iatrogenic injury by anticipating potential challenges.

Surgical management of intramedullary cervical spinal sarcoidosis complicated by transient unilateral weakness: A case report.

Background: Sarcoidosis, a multisystem inflammatory non-caseating granulomatous disease, can present with neurologic lesions in up to 10% of patients. Case Description: A 57-year-old male presented with three months of worsening upper extremity radicular pain associated with dysmetria, hyperreflexia, bilateral Hoffman's, and positive Babinski signs. The contrast magnetic resonance imaging (MRI) showed a diffuse T2 signal hyperintensity and T1-enhancing 2.5 cm lesion extending sagittally between C4 and C6. The cerebrospinal fluid analysis showed a high protein level and lymphocytic pleocytosis. A cardiac positron emission tomography scan was consistent with the diagnosis of cardiac sarcoidosis. With the diagnosis of multisystemic/probable neurosarcoidosis, the patient was unsuccessfully treated with intravenous methylprednisolone, followed by infliximab. Due to severe cord compression/myelopathy, a C3-C6 laminectomy and C3-C7 posterior spinal fusion were performed. Postoperatively, the patient developed a transient right-sided hemiparesis. Over nine postoperative months, the patient had four relapses of transient repeated episodes of paresis, although follow-up cervical MRI scans revealed adequate cord decompression with a stable intramedullary hyperintense lesion. Conclusion: Patients with neurosarcoidosis respond unpredictably to surgical decompression and require prolonged medical care, which is often unsuccessful.

The Benefit of an Umbrella Protocol: Reducing Challenges in Orthopedic Oncology Research.

Background: Orthopedic oncology research is hindered by the scarcity of musculoskeletal tumors and research administrative inefficiencies. This paper introduces observational research through an innovative institution-specific methodology-termed an umbrella protocol. This protocol outlines a comprehensive standard procedure to expedite ethical approval for future aligned studies, reducing administrative barriers to research. Methods: We developed an umbrella protocol at an academic center, involving meticulous methodological identification and coordination with the institutional review board (IRB) to adhere to local guidelines. The protocol encompasses identifying investigators, research objectives, study goals, and data and safety monitoring frameworks necessary for typical standards. Results: Implementation of the umbrella protocol took 110 days to achieve exemption status, following multiple discussions with the IRB and extensive revisions. At the authors institution, this protocol significantly reduces protocol review times from an average of six-to-eight weeks to nearly instantaneous, facilitating a streamlined research process. Additionally, we established a dedicated orthopedic oncology patient registry to enhance future research endeavors. Conclusions: The adoption of umbrella protocols represents a pioneering strategy in orthopedic oncology. This approach mitigates research administrative burdens and broadens research scope in the field. It underscores the necessity of IRB collaboration, methodological precision, and stringent data management. The article also reflects on the ethical implications and potential biases introduced by emerging technologies like artificial intelligence, advocating for diligent ethical oversight. The establishment of an umbrella protocol marks a significant step towards more efficient research methodologies, ultimately aiming to improve patient care and outcomes for individuals with rare musculoskeletal conditions.

Evaluating the safe zone for lumbar pedicle screws: are midline crossing screws indicative of pedicle breach?

BACKGROUND CONTEXT: Pedicle screw breach (PSB) is not uncommon following lumbar instrumentation, and in some instances, it may lead to vascular and/or neurologic complications. Previous literature suggested that screws crossing the vertebral midline on an anterior-posterior (AP) radiograph (or midsagittal on CT) are concerning for medial pedicle breach. OBJECTIVE: Our primary aim was to map out the safe zones (SZ) of bilateral pedicle instrumentation and their relationship at each lumbar vertebral level. Our secondary aim was to evaluate the presence of SZs' intersection at each lumbar level, denoting safe midline pedicle screw crossing not otherwise associated with medial pedicle breach. STUDY DESIGN/SETTING: Retrospective Anatomical Study. PATIENT SAMPLE: Adult patients in the from "The Cancer Imaging Archive" (TCIA) database who have not had thoraco-lumbo-sacral fusion. OUTCOME MEASURES: Physiologic measures obtained through 3D analysis of CT images and virtual pedicle screws. METHOD: CT scans of 51 patients were randomly selected from "The Cancer Imaging Archive" (TCIA) online database for analysis. The Sectra 3D Spine software was used to create 3D renderings, place virtual screws, and make measurements. At each lumbar vertebra, the right and left pedicle corridors were mapped. At each pedicle, two screw positions were templated, the "medial limit screw" (MLS) and the "lateral limit screw" (LLS). Each limit screw was the most extreme position that the screw could exist in without causing a medial or lateral breach. The safe zone was defined as the zone between MLS and LLS. Measurements were taken for each level (between L1 and L5) and side (Left, Right). RESULTS: A total of 253 lumbar vertebrae from 51 patients (mean age 53.1, 56.9% male) were included. Two vertebrae from two patients were removed for poor image quality. Out of the 506 screw positions analyzed in our study, 97.4% had overlapping SZ and crossed the midplane without medial pedicle breach. The significant factors (p<.01) for safe midplane-crossing screws included: the screw length (L1-L5); the laterality of the screw entry point (L1-L4); and the pedicle diameter (L2 and L5). CONCLUSIONS: A midline crossing pedicle screw on a lumbar AP radiograph is not necessarily indicative of a medial pedicle screw breach. Anatomical (ie, larger pedicle diameter) and technical (ie, longer screws, and lateral entry points) factors allow for safety zone intersections and indicate safe midline crossing by pedicle screws.

The "V" Sign: A Reliable Anatomic and Radiographic Landmark for Posterior Percutaneous S1 Screw Placement.

Background: Sacral (S1) pedicle screw misplacement in posterior percutaneous fixation (PPF) can be related to anatomical variability and a lack of reliable radiographic landmarks. This study highlights a reproducible anatomical landmark (the "V" sign) for the safe localization of the S1 pedicle entry point under fluoroscopy. Methods: Human cadavers (n = 14) were dissected for the anatomical description of the "V" landmark and its relationship with the entry point of the S1 pedicle screw. The "V" landmark was defined medially by the lateral border of the superior articulating process of S1 and laterally by the posterior projection of the sacral ala. The mean distance was measured between the bottom point of the "V" landmark and the anatomical entry point to the S1 pedicle (V-S1 entry point distance). A similar measurement was conducted on computed tomography (CT) scans of 135 patients who underwent PPF using the "V" sign as a landmark for S1 pedicle screw placement (270 screws). These were retrospectively evaluated for appropriateness of S1 screw entry points and for proper S1 screw alignment and breaches. Results: In the 14 cadavers, irrespective of the laterality and sex, the V-S1 entry point distance averaged 11.7 mm. On the medial-lateral axis, all entry points converged within 2 mm of a vertical line intersecting the base of the "V." Additionally, the CT scan analysis (135 patients, 270 screws) revealed an optimal entry point for 100% of the screws and a 3.3% (n = 9 screws) breach rate. Six of the 9 identified breaches were minor, and only 1 (0.4% of the 270 screws) warranted revision. Conclusions: The "V" sign serves as a reliable anatomical and radiographic landmark for identifying the S1 pedicle entry point under fluoroscopic guidance. This landmark can help surgeons overcome the radiographic ambiguity of the sacral anatomy and ultimately reduces the rate of S1 pedicle screw misplacement. Level of evidence: Diagnostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Antepsoas (ATP) Surgical Corridor for Lumbar and Lumbosacral Arthrodesis: A Radiographic, Anatomic, and Surgical Investigation.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: To investigate the size of prepsoas surgical corridors, developed between the iliopsoas and prespinal vessels, at all disk levels between L1 and S1 granted by left and right lateral antepsoas (ATP) approaches. Secondary aims include evaluation of presurgery radiographic prepsoas windows between L1 and S1 with respect to the intraoperative findings. SUMMARY OF BACKGROUND DATA: The ATP technique is an evolving alternative to the transpsoas and direct anterior exposures for lumbar fusion. However, the vascular morphometric data of the ATP approach remain underexplored, especially at L5-S1. MATERIALS AND METHODS: Patients indicated for ATP lumbar-lumbosacral fusion between September 2018 and February 2020 were enrolled (n=121). Data were collected prospectively, including the following (in mm): intraoperative manual measurements of the premobilization psoas-vessel (pre-PV) window, the final postmobilization psoas-vessel (post-PV) window, and the preoperative radiographic psoas-to-vessel distance at the respective studied disk levels. RESULTS: A total of 121 patients (75 female, mean age: 55.3 yr, 81.8% right-sided approach) underwent a total of 279 levels of spinal fusion. Irrespective of the ATP access laterality, we noted ample postmobilization psoas-vessel (post-PV differential) corridors: largest at L4-L5 (36-38 mm) followed by L5-S1 (31-35 mm), L3-L4 (32-33 mm), L2-L3 (28-30 mm), and L1-L2 (20-24 mm). Similarly, the relative increases of the psoas-vessel corridors (post-PV and pre-PV differentials, averaged: 31 mm at L5-S1, 32 mm at L4-L5, 26 mm at L3-L4, 25 mm at L2-L3, and 14 mm at L1-L2) were also significant in both lateral approaches. In right flank approaches, the right vascular structures projected more dorsally compared with left-sided vasculature ( P <0.05). CONCLUSION: The ATP access offers generous bilateral prepsoas surgical windows to L1-S1 intervertebral disks, allowing for a safe anterior column release, decompression, instrumentation, and fusion.

The Role of Minimally Invasive Percutaneous Pedicle Screw Fixation for the Management of Spinal Metastatic Disease.

OBJECTIVE: Optimal surgical management of spinal metastatic disease remains controversial. Skip and diffuse spinal lesions, patient frailty, and the need for timely adjuvant chemoradiation complicate surgical decision-making. Minimally invasive percutaneous pedicle screw fixation (MIPSF) is an attractive concept that can confer stability and allow early postoperative mobilization. To date, outcomes of the MIPSF technique remain under-investigated. METHODS: A single-center retrospective review of patients undergoing percutaneous instrumentation for multilevel spinal metastatic disease between January 2012 and October 2020 was performed. Twenty-four patients were identified, and their primary tumor diagnoses, modified Tokuhashi scores, Spine Instability Neoplastic Scores, neurologic functions, pain scores, and procedure types were noted. Of these patients, 17 underwent fixation of 6 or more levels (L-MIPSF), whereas 7 underwent fixation of <6 levels (S-MIPSF). All patients had screw-and-rod constructs placed percutaneously using bi-planar fluoroscopy guidance. Patients undergoing corpectomy, multilevel laminectomies, or open posterior instrumentation were excluded. RESULTS: Improvement in pain and neurological function was noted in nearly all patients who underwent MIPSF. Average skin incision-to-closing time was 130 minutes, and standard deviation of 55 minutes. Likewise, the average estimated operative blood loss was 402 mL, and standard deviation of 388 mL. Only one patient required hardware revision due to proximal loss of fixation. Two patients required mini-open decompression procedures due to tumor recurrence at different levels than the index pathology. CONCLUSIONS: Multilevel minimally invasive spinal fixation is feasible in patients with diffuse spinal metastasis. The percutaneous nature of the technique minimizes dissection, blood loss, and operative times. Early outcomes of MIPSF are promising and demonstrate utility in avoiding multiple subsequent procedures in a cohort of deconditioned patients.

Pseudarthrosis Following Lumbar and Lumbosacral Fusion Using the Antepsoas Technique.

STUDY DESIGN: Retrospective case-control study. OBJECTIVE: The aim of this study was to evaluate the prevalence of pseudarthrosis following antepsoas (ATP) lumbar and lumbosacral fusions. SUMMARY OF BACKGROUND DATA: Pseudarthrosis is a feared complication following spinal fusions and may affect their clinical outcomes. To date there are no sufficient data on the fusion rate following ATP lumbar and lumbosacral arthrodesis. METHODS: This is a retrospective review of 220 patients who underwent lumbar minimally invasive antepsoas (MIS-ATP) fusions between January 2008 and February 2019 who have at least 1-year postoperative computed tomography (CT) follow-up scans. Fusion was graded using CT scans imaging and adopting a 1-4 grading scale (1, definitely fused; 2, likely fused; 3, likely not fused; 4, definitely not fused/nonunion). Grades 3 or 4 indicate pseudarthrosis. RESULTS: A total of 220 patients (average age: 66 years, 82 males (37.2%), and 127 (57.7%) smokers) were included. Eight patients (3.6%) developed pseudarthrosis. A total of 693 discs were addressed using the ATP approach. Of those, 681 (98.3%) were considered fused (641 levels [92.5%] were "definitely fused" and 40 levels [5.8%] were "Likely fused") and 12 discs (1.7%) developed pseudarthrosis (seven levels [1.0%] were "likely not fused" and five levels (0.7%) were "definitely not fused"). The highest rate of pseudarthrosis was found at L5-S1 (4.8%) compared to the L1-L5 discs (0-2%). Of 127 smokers, six developed pseudarthrosis (odds ratio = 2.3, P = 0.3). The fusion rates were 95.3% and 97.8% for smokers and nonsmokers, respectively. Of the eight patients who developed pseudarthrosis, only four (50%) were symptomatic, of whom two (25%) required revision surgery. Both of these patients were smokers. The overall revision rate due to pseudarthrosis was 0.9% (two of 220 patients). CONCLUSION: The MIS-ATP technique results in a high fusion rate (96.4% of patients; 98.3% of levels). Pseudarthrosis was noted mostly at the L5-S1 discs and in smokers.Level of Evidence: 4.