Overreporting of the disc herniation in lumbar spine MRI scans performed for patients with spondylolisthesis.

BACKGROUND: Spondylolisthesis is often misdiagnosed on magnetic resonance imaging (MRI) as the slip may reduce to a normal alignment when the patient lies supine. Often, disc herniation is reported at the level of spondylolisthesis. PURPOSE: To determine the incidence rates of disc herniation at the level of spondylolisthesis. MATERIAL AND METHODS: This is a retrospective study included 258 consecutive patients with spondylolisthesis who had lumbar spine MRI. The archived reports were collectively put in Group 1. A musculoskeletal radiologist and a spine surgeon reviewed the imaging studies together. Their readings were referred to as Group 2. The findings of both groups were compared to evaluate whether disc herniation was overreported. RESULTS: Group 1 reported findings of true disc herniation in 112 (41.6%) cases and pseudo disc herniation or no findings of disc herniation at the level of spondylolisthesis in 157 (58.4%) cases. Group 2 reported findings of a true disc herniation in 25 (9.3%) cases and pseudo disc herniation or no findings of disc herniation in the remaining 244 (90.7%) cases. There was a statistically significant difference in the reporting rates between these two groups (P < 0.02). The most overreported finding was the disc bulging (P < 0.01). CONCLUSION: The current study showed overreporting of disc herniation in lumbar spine MRI scans performed for patients with established spondylolisthesis. The majority of disc pathology at the level of spondylolisthesis are pseudo disc rather than a true disc herniation. An accurate diagnosis is vital in planning surgical intervention.

Iatrogenic muscle damage in transforaminal lumbar interbody fusion and adjacent segment degeneration: a comparative finite element analysis of open and minimally invasive surgeries.

PURPOSE: Lumbar procedures for Transforaminal Lumbar Interbody Fusion (TLIF) range from open (OS) to minimally invasive surgeries (MIS) to preserve paraspinal musculature. We quantify the biomechanics of cross-sectional area (CSA) reduction of paraspinal muscles following TLIF on the adjacent segments. METHODS: ROM was acquired from a thoracolumbar ribcage finite element (FE) model across each FSU for flexion-extension. A L4-L5 TLIF model was created. The ROM in the TLIF model was used to predict muscle forces via OpenSim. Muscle fiber CSA at L4 and L5 were reduced from 4.8%, 20.7%, and 90% to simulate muscle damage. The predicted muscle forces and ROM were applied to the TLIF model for flexion-extension. Stresses were recorded for each model. RESULTS: Increased ROM was present at the cephalad (L3-L4) and L2-L3 level in the TLIF model compared to the intact model. Graded changes in paraspinal muscles were seen, the largest being in the quadratus lumborum and multifidus. Likewise, intradiscal pressures and annulus stresses at the cephalad level increased with increasing CSA reduction. CONCLUSIONS: CSA reduction during the TLIF procedure can lead to adjacent segment alterations in the spinal element stresses and potential for continued back pain, postoperatively. Therefore, minimally invasive techniques may benefit the patient.

Lumbar spine fusion outcomes using a cellular bone allograft with lineage-committed bone-forming cells in 96 patients.

BACKGROUND: Instrumented posterior lumbar fusion (IPLF) with and without transforaminal interbody fusion (TLIF) is a common treatment for low back pain when conservative interventions have failed. Certain patient comorbidities and lifestyle risk factors, such as obesity and smoking, are known to negatively affect these procedures. An advanced cellular bone allograft (CBA) with viable osteogenic cells (V-CBA) has demonstrated high fusion rates, but the rates for patients with severe and/or multiple comorbidities remain understudied. The purpose of this study was to assess fusion outcomes in patients undergoing IPLF/TLIF using V-CBA with baseline comorbidities and lifestyle risk factors known to negatively affect bone fusion. METHODS: This was a retrospective study of de-identified data from consecutive patients at an academic medical center who underwent IPLF procedures with or without TLIF, and with V-CBA. Baseline patient and procedure characteristics were assessed. Radiological outcomes included fusion rates per the Lenke scale. Patient-reported clinical outcomes were evaluated via the Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) for back and leg pain. Operating room (OR) times and intraoperative blood loss rates were also assessed. RESULTS: Data from 96 patients were assessed with a total of 222 levels treated overall (mean: 2.3 levels) and a median follow-up time of 16 months (range: 6 to 45 months). Successful fusion (Lenke A or B) was reported for 88 of 96 patients (91.7%) overall, including in all IPLF-only patients. Of 22 patients with diabetes in the IPLF+TLIF group, fusion was reported in 20 patients (90.9%). In IPLF+TLIF patients currently using tobacco (n = 19), fusion was reported in 16 patients (84.3%), while in those with a history of tobacco use (n = 53), fusion was observed in 48 patients (90.6%). Successful fusion was reported in all 6 patients overall with previous pseudarthrosis at the same level. Mean postoperative ODI and VAS scores were significantly reduced versus preoperative ratings. CONCLUSION: The results of this study suggest that V-CBA consistently yields successful fusion and significant decreases in patient-reported ODI and VAS, despite patient comorbidities and lifestyle risk factors that are known to negatively affect such bony healing.

Clinical outcome and subsequent sequelae of cement extravasation after percutaneous kyphoplasty and vertebroplasty: a comparative review.

Background Injection of cement during vertebroplasty and kyphoplasty can leak into surrounding structures and could be symptomatic. Purpose To identify the sites and incidence of cement extravasation after kyphoplasty and vertebroplasty, and to evaluate their impacts on clinical outcomes. Material and Methods A retrospective review of 316 patients treated with kyphoplasty and vertebroplasty; 411 cases were included (223 kyphoplasty and 188 vertebroplasty). Cement extravasation was evaluated postoperatively by computed tomography (CT) scan of the spine. Clinical outcomes were assessed by visual analog scale (VAS) and Oswestry Disability Index (ODI). Results There was a statistically significant difference in the incidence rate of cement extravasation between vertebroplasty and kyphoplasty groups ( P < 0.04). The most common site of cement extravasation was in paravertebral soft tissues for vertebroplasty (n = 33, 40.7%) and for kyphoplasty (n = 30, 30%). In the subgroup where cement leaked into the intradiscal space, adjacent vertebral body fractures occurred in 3/26 vertebrae (11.5%) in the vertebroplasty group and in 2/18 vertebrae (11.1%) in the kyphoplasty group. Both groups showed a statistically significant decrease in both VAS ( P < 0.001) and ODI scores ( P < 0.001). There was no significantly difference in patient satisfaction between those who had cement extravasation and those who did not, in both groups. Conclusion Kyphoplasty has an advantage in terms of less risk of cement extravasation. However, this factor did not reflect on subsequent sequelae or final clinical outcomes. This study did not find a distinct correlation between intradiscal cement extravasation and increased risk of adjacent vertebral fractures.

Effectiveness and safety of transforaminal lumbar interbody fusion in patients with previous laminectomy.

PURPOSE: To determine the efficacy and safety of transforaminal lumbar interbody fusion (TLIF) for revision lumbar spine surgery in patients with previous laminectomy. The secondary objective was to evaluate the clinical and radiological outcome after such a procedure. METHODS: Retrospective case series study. Eighty-two patients were included. There were 48 women (58.5 %) and 34 men (41.5 %) with a mean age of 51 years (range 26-84) at the time of index procedure. The outpatient and inpatient charts were reviewed to identify patients' demographic data, preoperative, perioperative, and postoperative data. The outcome measures were assessed by Oswestry Disability Index (ODI) and visual analog scale (VAS) for back and leg pain. An independent spine surgeon and musculoskeletal radiologist reviewed the imaging studies. RESULTS: The average operative time was 160 min (range 131-250). The average estimated blood loss was 652 cc (100-1,400 cc). Nineteen patients (23.1 %) required blood transfusion. Five patients (6 %) had dural tear. One patient (1.2 %) had a surgical site infection. Two patients (2.4 %) had thromboembolic events. The average hospital stay was 3.8 days (2-5 days). At a mean follow-up of 28 months, there were statically significant improvement in the ODI and VAS for back and leg pain. None of the patients' radiographs showed hardware failure or pedicle screw loosening and no patient returned to the operating room for pseudarthrosis. CONCLUSIONS: The current study confirmed that TLIF approach in patients with previous laminectomy is effective and safe with good outcomes.

A clinical review of hand manifestations of cervical myelopathy, cervical radiculopathy, radial, ulnar, and median nerve neuropathies.

Cervical spondylotic myelopathy (CSM) is defined as compression of the spinal cord in the neck, resulting in problems with fine motor skills, hand numbness, pain or stiffness of the neck, and difficulty walking due to loss of balance. Brachial plexus (BP) neuropathies arise due to compression to any distal branches arising from C5-T1, whereas cervical radiculopathy involves compression at the nerve root in the neck. Such conditions can present with variable degrees of musculoskeletal pain, weakness, sensory changes, and reflex changes. The pronounced convergence in symptomatic manifestation within these conditions can pose a formidable challenge to clinicians, particularly in primary care. Thus, the primary objective of this paper is to enhance clarity and distinction among these pathological conditions. This objective is pursued through comprehensive delineation of the dermatomal and myotomal distributions characteristic of each condition. Furthermore, a meticulous examination is undertaken to elucidate physical indicators and maneuvers that exhibit a notably high sensitivity in detecting these conditions. Accurate diagnosis and treatment of each nerve pathology is important as long-term spinal cord compression and its roots may result in permanent disability and severely impact one's quality of life. As such, this systematic review serves as a guide that aids clinicians in differentiating the aforementioned conditions based on anatomy, physical exam findings, and imaging studies. Furthermore, this study aims to outline common peripheral nerve neuropathies in the upper extremities and ways to mitigate these pathologies using the least to most invasive treatment modalities.

Diabetes increases risk of lumbar spinal fusion complications: association with altered structure of newly formed bone at the fusion site.

Diabetes predisposes to spine degenerative diseases often requiring surgical intervention. However, the statistics on the prevalence of spinal fusion success and clinical indications leading to the revision surgery in diabetes are conflicting. The purpose of the presented retrospective observational study was to determine the link between diabetes and lumbar spinal fusion complications using a database of patients (n = 552, 45% male, age 54 ± 13.7 years) residing in the same community and receiving care at the same health care facility. Outcome measures included clinical indications and calculated risk ratio (RR) for revision surgery in diabetes. Paravertebral tissue recovered from a non-union site of diabetic and nondiabetic patients was analyzed for microstructure of newly formed bone. Diabetes increased the RR for revision surgery due to non-union complications (2.80; 95% CI, 1.12-7.02) and degenerative processes in adjacent spine segments (2.26; 95% CI, 1.45-3.53). In diabetes, a risk of revision surgery exceeded the RR for primary spinal fusion surgery by 44% (2.36 [95% CI, 1.58-3.52] vs 1.64 [95% CI, 1.16-2.31]), which was already 2-fold higher than diabetes prevalence in the studied community. Micro-CT of bony fragments found in the paravertebral tissue harvested during revision surgery revealed structural differences suggesting that newly formed bone in diabetic patients may be of compromised quality, as compared with that in nondiabetic patients. In conclusion, diabetes significantly increases the risk of unsuccessful lumbar spine fusion outcome requiring revision surgery. Diabetes predisposes to the degeneration of adjacent spine segments and pseudoarthrosis at the fusion sites, and affects the structure of newly formed bone needed to stabilize fusion.

Pedicle Screw Track Augmentation With Fibular Allograft for Significant Bone Loss in Revision Fixation.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To report the clinical and radiological outcomes for screw track augmentation with fibular allograft in revision of loose pedicle screws associated with significant bone loss along the screw track. METHODS: Thirty consecutive patients, 18 men (60%) and 12 women (40%), with a mean age 52 years (range 34- 68). Fibular allograft was prepared by cutting it into longitudinal strips 50 mm in length. Three allograft struts were inserted into the screw track. Six mm tap used to tap between the 3 fibular struts. Eight- or 9-mm diameter, and 45 or 50 mm in length screw was then inserted. The clinical outcomes were assessed by means of the Oswestry Disability Index (ODI), and visual analog scale (VAS) for back and leg pain for clinical outcome. Computed tomography scan (CT) performed at 12 months postoperative visit to assess fibular graft incorporation along the pedicle screw track, any screw loosening and the interbody as well as posterolateral fusion. RESULTS: At a mean follow up of 29 months, there were statically significant improvement in the ODI and VAS for back and leg pain. CT scan obtained at last follow-up showed incorporation of fibular allograft and solid fusion in all patients except one. CONCLUSION: The fibular allograft augmentation of the pedicle screw track in revision of loose pedicle screws associated with significant bone loss is a viable option. It allows for biologic fixation at the screw-bone interface and has some key advantages when compared to currently available methods.

Effects of Sacral Slope Changes on the Intervertebral Disc and Hip Joint: A Finite Element Analysis.

OBJECTIVE: Spinopelvic parameters are vital components that must be considered when treating patients with spinal disease. Several finite element (FE) studies have explored spinopelvic parameters such as sacral slope (SS) and the impact on the lumbar spine, although no study has examined the effect on the hip and sacroiliac joint (SIJ) on varying SS angles. Therefore, it is necessary to have a biomechanical understanding of the impact on the spinopelvic complex. METHODS: An FE lumbar, pelvis, and femur model was created from computed tomography scans of a 55-year-old female patient with no abnormalities. Three models were created: a normal model (SS = 26°), a model with high SS (SS = 30°), and a model with low SS (SS = 20°). These models underwent loading for flexion, extension, lateral bending, and axial rotation. Range of motion (ROM), intradiscal pressures, hip joint, and SIJ contact stresses were analyzed. RESULTS: The high SS model (SS = 30°) indicated the highest ROM in the L5-S1 (slip angle) level and the highest intradiscal pressures. The highest average hip and SIJ contact stresses were present in this model, although the low SS model (SS = 20°) in extension had the largest stresses for the hip and SIJ. CONCLUSIONS: The results provide evidence that patients with higher SS may be more prone to increased ROM at the slip angle (L5-S1). In addition, patients with higher SS were shown to have higher contact stresses on the hip joint and SIJ, potentially leading to SIJ dysfunction. Clinically, correcting lumbar lordosis including SS is important; however, a high SS may have a negative impact on the intervertebral disc, SIJ, and hip joint.

Spondyloarthropathies That Mimic Ankylosing Spondylitis: A Narrative Review.

Ankylosing spondylitis is the most common type of seronegative inflammatory spondyloarthropathy often presenting with low back or neck pain, stiffness, kyphosis and fractures that are initially missed on presentation; however, there are other spondyloarthropathies that may present similarly making it a challenge to establish the correct diagnosis. Here, we will highlight the similarities and unique features of the epidemiology, pathophysiology, presentation, radiographic findings, and management of seronegative inflammatory and metabolic spondyloarthropathies as they affect the axial skeleton and mimic ankylosing spondylitis. Seronegative inflammatory spondyloarthropathies such as psoriatic arthritis, reactive arthritis, noninflammatory spondyloarthropathies such as diffuse idiopathic skeletal hyperostosis, and ochronotic arthritis resulting from alkaptonuria can affect the axial skeleton and present with symptoms similar those of ankylosing spondylitis. These similarities can create a challenge for providers as they attempt to identify a patient's condition. However, there are characteristic radiographic findings and laboratory tests that may help in the differential diagnosis. Axial presentations of seronegative inflammatory, non-inflammatory, and metabolic spondyloarthropathies occur more often than previously thought. Identification of their associated symptoms and radiographic findings are imperative to effectively diagnose and properly manage patients with these diseases.

Do design variations in the artificial disc influence cervical spine biomechanics? A finite element investigation.

Various ball and socket-type designs of cervical artificial discs are in use or under investigation. Many artificial disc designs claim to restore the normal kinematics of the cervical spine. What differentiates one type of design from another design is currently not well understood. In this study, authors examined various clinically relevant parameters using a finite element model of C3-C7 cervical spine to study the effects of variations of ball and socket disc designs. Four variations of ball and socket-type artificial disc were placed at the C5-C6 level in an experimentally validated finite element model. Biomechanical effects of the shape (oval vs. spherical ball) and location (inferior vs. superior ball) were studied in detail. Range of motion, facet loading, implant stresses and capsule ligament strains were computed to investigate the influence of disc designs on resulting biomechanics. Motions at the implant level tended to increase following disc replacement. No major kinematic differences were observed among the disc designs tested. However, implant stresses were substantially higher in the spherical designs when compared to the oval designs. For both spherical and oval designs, the facet loads were lower for the designs with an inferior ball component. The capsule ligament strains were lower for the oval design with an inferior ball component. Overall, the oval design with an inferior ball component, produced motion, facet loads, implant stresses and capsule ligament strains closest to the intact spine, which may be key to long-term implant survival.

Clinical presentation and surgical anatomy of sympathetic nerve injury during lumbar spine surgery: a narrative review.

Background and Objective: To highlight the surgical anatomy, procedural variations, presentation, and management of sympathetic nerve injury after surgery of the lumbar spine. Methods: PubMed and Google Scholar were searched for publications that were completed between 1951 and 2021. Relevant full-text articles published in the English language were selected and critically reviewed. Key Content and Findings: Sympathetic injury is a highly variable postsurgical complication with a greater incidence after an anterior or oblique approach to the lumbar spine compared to posterior and lateral approaches. The direct and extreme lateral approaches reduce the need to disturb sympathetic nerves thus reducing the risk of complications. It can present in multiple manners, including complex regional pain syndrome (CRPS) and retrograde ejaculation. These complications can be transient and resolve spontaneously or be treated with medications, physical therapy, and spinal blocks. The severity of the conditions and extent of recovery can vary drastically, with some patients never fully recovering. Conclusions: To access the lumbar spine, there are operational approaches and techniques that should be used to decrease the risk of intraoperative injury. It is crucial to understand the advantages and risks to different approaches and take the necessary steps to minimize complications. Early identification of dysfunction and adequate management of symptoms are imperative to effectively manage patients with lumbar sympathetic trunk and sympathetic nerve fiber injuries.

Intracranial hemorrhage after spinal surgery: a literature review.

Background and Objective: Intracranial hemorrhage following spinal surgery is an infrequent but severe complication. Due to its rarity, the etiology, clinical characteristics, and treatment have not yet been fully elucidated. This literature review analyzed the incidence, clinical manifestations, hemorrhage location, current therapeutic strategies, location of operation, and interval time between surgery and bleeding. The objectives of the article were to provide insights for clinicians to promptly identify and prevent potential cases of intracranial hemorrhage. Methods: The authors queried PubMed and Web of Science databases using predefined keywords and included published literature reporting on intracranial hemorrhage after spinal surgery. Relevant case reports, case series, and reviews describing the mechanism of intracranial hemorrhage after spinal surgery and meeting diagnostic criteria for intracranial hemorrhage related to spinal surgery were included. Clinico-demographc data, presentations symptoms, location, index surgery type, and neurological outcomes after brain hemorrhage. Oxford Centre Level of Evidence guidelines was used to evaluate the quality of included studies. Descriptive statistics were used to synthesize the results. Key Content and Findings: A total of 80 publications of level of evidence IV involving 108 patients with median age at diagnosis was 58.5 years (inter-quartile range: 6-85) were analyzed. The incidence of intracranial hemorrhage was 0.08-0.37% among patients who underwent spinal surgery, and this complication occurred predominantly within 48 hours postoperatively. The initial presentation included headache, reduced level of consciousness, dysarthria, nausea, vomiting, hearing loss, blurred vision, neck rigidity, and delayed recovery from anesthesia. More than half (58.3%) of patients improved, while 23.1% still experienced neurological dysfunctions, and 7.4% died. Conclusions: The present study is limited by the levels of evidence of the included studies. There is heterogeneity among cases with respect to patient demographics and medical history. Angiography is critical in assessing the presence and extent of underlying vascular diseases. Intracranial hemorrages may be caused by intraoperative or postoperative cerebrospinal fluid leakage that will lead to intracranial pressure change and induced by intracranial venous or arterial bleeding. The treatment strategies include conservative medical management and surgical treatment. Individualized treatment should be emphasized.

Revision internal fixation and nonvascular fibular graft for femoral neck nonunion.

BACKGROUND: The rates of nonunion after internal fixation for femoral neck fractures have been reported to range from 0% to 59%. Existing treatment options are osteotomy (with or without graft), osteosynthesis using various implants and grafting techniques (muscle pedicle, vascularized, and nonvascularized fibula), or arthroplasty. The objective of this study was to assess the outcome results of revision internal fixation and nonvascular fibular bone grafting for symptomatic aseptic femoral neck nonunion. METHODS: This is a retrospective case series study involving 17 patients with symptomatic femoral neck nonunion that were treated with revision internal fixation and fibular bone graft. The inclusion criteria were aseptic symptomatic femoral neck nonunion with no or minimal varus alignment. There were eight men and nine women. The average age was 46 years (range, 24-58 years). Thirteen patients had autogenous fibular bone graft, and six patients had fibular allograft. RESULTS: Of the 13 patients who had autogenous nonvascularized fibular bone grafts, four remained in nonunion. Fibular autograft had a 69.2% success rate with the mean time to union 4.8 months. Four of the six patients who had fibular allografts remained in nonunion. Fibular allograft had a 33.3% success rate with the mean time to union 13.3 months. CONCLUSION: This study showed that revision internal fixation and fibular autograft have resulted into a better and faster union rate than fibular allografts.

Epidural hematoma associated with occult fracture in ankylosing spondylitis patient: a case report and review of the literature.

STUDY DESIGN: A case report and review of the literature. OBJECTIVE: To highlight the risk of occult fracture associated with symptomatic epidural hematoma in patient with ankylosing spondylitis. SUMMARY OF BACKGROUND DATA: Hyperextension injuries are common in patients with ankylosed spine. Failure of standard imaging to detect these fractures may result in delayed diagnosis. Ossification of the ligaments in these patients makes even subtle fractures grossly unstable owing to the increased lever arm. Delayed diagnosis of fractures may result in further displacement and increased risk of neurological injury. METHODS: The clinical findings, roentgenographic appearance, and treatment were presented. RESULTS: A 69-year-old patient with a history of ankylosing spondylitis fell 9 feet from a ladder. The patient developed pain in his neck and numbness in his hands. Initial computed tomography (CT) scan of spine showed a subtle fracture in the vertebral body of C7. A magnetic resonance imaging scan showed an epidural hematoma extending from C5 to T3. The patient was taken to the operating room urgently for decompression. Laminectomy was performed from C5 to T3 and a large epidural hematoma was evacuated. After decompression the patient had some improvement in his neurological status. A postdecompression repeat CT scan revealed obvious fracture at C6-C7 with anterior distraction indicating a hyperextension injury. The patient was taken back to the operating room within 16 hours of his decompression for C4 to T3 posterior segment instrumentation and fusion. CONCLUSIONS: Patients with ankylosing spondylitis who sustain low-energy injuries should be considered to have a fracture especially if they develop epidural hematoma. A high index of suspicion is necessary in such a case. Imaging studies including magnetic resonance imaging and CT scans should be reviewed carefully to rule out any occult fracture.

High Prevalence of Biofilms on Retrieved Implants from Aseptic Pseudarthrosis Cases.

INTRODUCTION: Recent literature has associated pseudarthrosis and pedicle screw loosening with subchronic infection at the pedicle of the vertebra. The positive culture results of a previous retrieval analysis show that such patients have a high frequency of bacterial contamination. The objective of this study is to visually capture the architecture of these undiagnosed infections, which have been described in other studies as biofilms on supposedly "aseptic" screw loosening. METHODS: Explants from 10 consecutive patients undergoing revision spine surgery for pseudarthrosis were collected and fixed in glutaraldehyde solution. Each of these implants was imaged thoroughly by using scanning electron microscopy and x-ray spectroscopy to evaluate the architecture of the biofilm. Additionally, eight patient swabs from tissues around the implants were sent for cultures to assess bacterial infiltration in tissues beyond the biofilm. The implants were also analyzed using energy dispersive x-ray spectroscopy. The exclusion criteria included clinically diagnosed infection (current or previous) and/or mechanical failure of the implant due to falls/accidents. RESULTS: The study was successful in capturing the visual architecture of the biofilm on retrieved implants. A total of 77% of pseudarthrosis cases presented with loose pedicle screws, which were diagnosed by a preoperative computed tomography scan showing radiolucency along the screw track and were confirmed intraoperatively, and 72% of the cases showed biofilm on explants. CONCLUSIONS: In the absence of the clinical presentation of infection, impregnated bacteria could form a biofilm around an implant, and this biofilm can remain undetected via contemporary diagnostic methods, including swabbing. Implant biofilm is frequently present in "aseptic" pseudarthrosis cases.

Computed tomography of normal distal tibiofibular syndesmosis.

OBJECTIVE: The purpose of this study was to determine the shape and measurements of the normal distal tibiofibular syndesmosis on computed tomographic scans and to identify features that could aid in the diagnosis of syndesmotic diastasis using computed tomography (CT). MATERIALS AND METHODS: CT scans of 100 patients with normal distal tibiofibular syndesmoses were reviewed retrospectively. In 67% the incisura fibularis was deep, giving the syndesmosis a crescent shape. In 33% the incisura fibularis was shallow, giving the syndesmosis a rectangular shape. The measurements of both types were taken using the same reference points. RESULTS: The mean age of the patients was 40 years, and there were 53 men and 47 women. The mean width of the distal tibiofibular syndesmosis anteriorly between the tip of the anterior tibial tubercle and the nearest point of the fibula was 2 mm. The mean width of the distal tibiofibular syndesmosis posteriorly between the medial border of the fibula and the nearest point of the lateral border of the posterior tibial tubercle was 4 mm. In men the mean width of the distal tibiofibular syndesmosis, anterior and posterior, was 2 mm and 5 mm, respectively, and in women it was 2 mm and 4 mm, respectively. CONCLUSION: This study provides measurements of the normal tibiofibular syndesmosis to aid in the diagnosis of occult diastasis.

Biomechanics of the Sacroiliac Joint: Surgical Treatments.

BACKGROUND: Fixation is one of the most common surgical techniques for the treatment of chronic pain originating from the sacroiliac joint (SIJ). Many studies have investigated the clinical outcomes and biomechanics of various SIJ surgical procedures. However, the biomechanical literature points to several issues that need to be further explored, especially for the devices used in minimally invasive surgery of the SIJ. This study (part II) aims to assess biomechanical literature to understand the existing information as it relates to efficacies of the surgical techniques and the gaps in the knowledge base. Part I reviewed basic anatomy and mechanics of the SIJ joint, including difference between males and females, and causes of pain emanating from these joints. METHODS: A thorough literature review was performed pertaining to studies related to SIJ fixation techniques and the biomechanical outcomes of the surgical procedures. RESULTS: Fifty-five studies matched the search criteria and were considered for the review. These articles predominantly pertained to the biomechanical outcomes of the minimally invasive surgery with different instrumentation systems and surgical settings. CONCLUSIONS: The SIJ is one of the most overlooked sources of lower back pain. The joint is responsible for the pain in 15% to 30% of people suffering from lower back pain. Various studies have investigated the clinical outcomes of different surgical procedures intended to improve the pain and quality of life following surgery. The data show that these techniques are indeed effective. However, clinical studies have raised several issues, like optimal number and positioning of implants, unilateral versus bilateral placements, adjacent segment disease, implant designs, and optimal location of implants with respect to variations in bone density across the SIJ. Biomechanical studies using in vitro and in silico techniques have addressed some of these issues. Studies also point out the need for additional investigations for a better understanding of the underlying mechanics for the improved long-term surgical outcomes. Further long-term clinical follow-ups are essential as well. This review presents pertinent findings.

Updates on Evidence-Based Practices to Reduce Preoperative and Intraoperative Contamination of Implants in Spine Surgery: A Narrative Review.

The current communication seeks to provide an updated narrative review on latest methods of reducing implant contaminations used during spine surgery. Recent literature review has shown that both preoperative reprocessing and intraoperative handling of implants seem to contaminate implants. In brief, during preoperative phase, the implants undergo repeated bulk cleaning with dirty instruments from the OR, leading to residue buildup at the interfaces and possibly on the surfaces too. This, due to its concealed nature, remains unnoticed by the SPD (sterile processing department) or other hospital staff. Nevertheless, these can be avoided by using individually prepackaged presterilized implants. In the intraoperative phase, the implants (in the sterile field) are directly touched by the scrub tech with soiled (assisting the surgeon dispose the tissues from the instruments in use) gloves for loading onto an insertion device. It is then kept exposed on the working table (either separately or next to the used instruments as the pedicles hole are being prepared). Latest investigation has shown that by the time it is implanted in the patient, it can harbor up to 10e7 bacterial colony-forming units. The same implants were devoid of such colony-forming units, when sheathed by an impermeable sterile sheath around the sterile implant.

Biomechanics of the Sacroiliac Joint: Anatomy, Function, Biomechanics, Sexual Dimorphism, and Causes of Pain.

BACKGROUND: The sacroiliac joints (SIJs), the largest axial joints in the body, sit in between the sacrum and pelvic bones on either side. They connect the spine to the pelvis and thus facilitate load transfer from the lumbar spine to the lower extremities. The majority of low back pain (LBP) is perceived to originate from the lumbar spine; however, another likely source of LBP that is mostly overlooked is the SIJ. This study (Parts I and II) aims to evaluate the clinical and biomechanical literature to understand the anatomy, biomechanics, sexual dimorphism, and causes and mechanics of pain of the SIJ leading to conservative and surgical treatment options using instrumentation. Part II concludes with the mechanics of the devices used in minimal surgical procedures for the SIJ. METHODS: A thorough review of the literature was performed to analyze studies related to normal SIJ mechanics, as well as the effects of sex and pain on SIJ mechanics. RESULTS: A total of 65 studies were selected related to anatomy, biomechanical function of the SIJ, and structures that surround the joints. These studies discussed the effects of various parameters, gender, and existence of common physiological disorders on the biomechanics of the SIJ. CONCLUSIONS: The SIJ lies between the sacrum and the ilium and connects the spine to the pelvic bones. The SIJ transfers large bending moments and compression loads to lower extremities. However, the joint does not have as much stability of its own against the shear loads but resists shear due the tight wedging of the sacrum between hip bones on either side and the band of ligaments spanning the sacrum and the hip bones. Due to these, sacrum does not exhibit much motion with respect to the ilium. The SIJ range of motion in flexion-extension is about 3°, followed by axial rotation (about 1.5°), and lateral bending (about 0.8°). The sacrum of the female pelvis is wider, more uneven, less curved, and more backward tilted, compared to the male sacrum. Moreover, women exhibit higher mobility, stresses/loads, and pelvis ligament strains compared to male SIJs. Sacroiliac pain can be due to, but not limited to, hypo- or hypermobility, extraneous compression or shearing forces, micro- or macro-fractures, soft tissue injury, inflammation, pregnancy, adjacent segment disease, leg length discrepancy, and prior lumbar fusion. These effects are well discussed in this review. This review leads to Part II, in which the literature on mechanics of the treatment options is reviewed and synthesized.