Distal Level Research Articles

Intercondylar notch volume in patients with posterior cruciate ligament tears and tibial avulsion injuries: a study applying computed tomography

BackgroundTwo relatively common forms of injury exist in the posterior cruciate ligament (PCL) after the onset of trauma: PCL tear and tibial avulsion fracture. The mechanism for the occurrence of these different forms of injury is not known. Herein, we aimed to investigate this mechanism by comparing the intercondylar notch parameters between patients with PCL tears and those with PCL avulsion fractures of the tibial insertion.MethodsFifty-three patients with PCL tears (37 male, 16 female: median age of 37 years: range 18–54 years) and 46 patients with avulsion fractures of tibial insertion (33 male, 13 female: median age of 33 years: range 18–55 years) were included in this study. Three-dimensional computed tomography (CT) was applied to measure the intercondylar notch width index and intercondylar notch volume. The intercondylar notch volume was simulated as the truncated-pyramid shape. Measurements of the top and bottom areas of this model were conducted on the slice containing the most proximal (S1) and most distal (S2) levels of Blumensaat’s line. Femoral condyle height (h) was defined as the vertical distance between two parallel planes, and the volume was calculated as h(S1 + S2 + √(S1S2))/3. The values of S1, S2, h, notch volume, the body mass index (BMI), intercondylar notch width (NW), femoral condylar width (FW) and notch width index (NWI) were compared among the PCL tear and avulsion-fracture groups.ResultsThe results show a significant difference in the S2 and normalized intercondylar notch volumes among patients with PCL tears and tibial avulsion injuries. Patients with PCL tears have smaller S2 and intercondylar notch volumes than those with tibial avulsion. There were no significant differences between the two groups in S1 or the 2D notch measurement parameters, such as the NW, FW and NWI. In addition, logistic regression analysis revealed notch volume and body mass index (BMI) as two significant independent predictors for PCL tears.ConclusionDecreased intercondylar notch volume and increased BMI are associated with an increased incidence of PCL tears. The occurrence of PCL tears and tibial avulsion injuries is influenced by the femoral intercondylar notch volume, and the measurement of the notch volume could be useful for identifying patients at risk for PCL tears.

Discussion

Discussion

Factors associated with stunting among children 0 to 59 months of age in Angola: A cross-sectional study using the 2015-2016 Demographic and Health Survey.

Stunting among children under five years of age is a serious public health problem globally, with life-long consequences to health, well-being, and productivity. Stunted growth has complex and multifactorial causes, reflecting the interaction of a broad range of conditions that determine child health. The Angola 2015-2016 Demographic and Health Survey (DHS) collected nationally representative anthropometry for 6,359 children 0 to 59 months of age in Angola, and ascertained exposure to a wide range of child, parental, socio-economic, and geographic variables. This study used a cross-sectional design to identify exposures associated with stunting among children 0 to 59 months of age in Angola, while considering the multifactorial and multi-level causes of stunting. Main outcome was prevalence of stunting, defined as proportion of children with height-for-age Z-score (HAZ) two or more standard deviations below the median. Prevalence of stunting was associated with individual, household, and area-level exposure variables, including child age and sex, birth order, birthweight, diarrhea, maternal and paternal age and education, source of water, sanitary system, and province. In conclusion, prevalence of stunting in Angola is associated with several factors previously described in the literature. Stunting is associated with exposures at the distal, intermediate, and proximal levels, in line with the framework on the causes of childhood malnutrition. This study identifies opportunities for interventions at multiple levels to decrease prevalence of stunting among children in Angola. Main limitations of this study are the potential for survival bias and residual confounding.

Research impact as understood by two funders of agricultural research in South Africa

Abstract Impact literacy is the understanding of research impact in terms of a junction of three elements: ‘what’, ‘how’ and ‘who’. ‘What’ refers to impact endpoints, that is, the medium- to long-term impacts or even short-term effects that occur during or immediately after research. ‘How’ refers to the understanding of how impact is created, in other words the interactions required. ‘Who’ focuses on which stakeholders need to be integrated into a network of interactions to contribute to impact. This study focused on the ‘what’ of impact, specifically on the understanding of research impact by two funders of agricultural research in South Africa. Members of specialist committees at the two funding organizations were asked, through a survey, to rate several structured items mapped on a research impact classification scheme. They could also provide their own ideas on what impact is. Committee members from both organizations viewed research impact primarily as an effect on the individuals and groups in the industry that they represent. They generally did not consider research impact as an effect on researchers, nor did they place specific emphasis on the societal effects of research. The ‘what’ of research impact was found to imply a series of effects, where the different effects build on each other. Linking these effects to the ‘how’ and ‘who’ of impact will require the construction of impact pathways. Funders should take responsibility for pushing research results to a distal level by planning ‘who’ will do the push, ‘how’ it will be done and managed, and to ‘what’ final aim.

Morphometry of extensors of the thumb with comprehensive review

This study was aimed to evaluate the anatomical variations and morphometry of long extrinsic tendons of the thumb namely, extensor pollicis longus and extensor pollicis brevis. Fiftyfive upper limbs of formalin embalmed adult cadavers were dissected. The variation in muscle belly, tendon, its course within dorsal wrist compartment and mode of insertion were noted. The extensor pollicis longus was duplicated in 5.5%. Around 25% tendons were fused with extensor pollicis brevis and through the extensor hood insert into the base of the distal phalanx. The extensor pollicis brevis was absent in 2% and tendon was also duplicated in 2%. In case of absent extensor pollicis brevis tendon, one of the slips from the abductor pollicis longus insert into base of the proximal phalanx instead of the extensor pollicis brevis. The extensor pollicis brevis tendon showed various modes of insertion. The overall length of the extensor pollicis longus and extensor pollicis brevis were 121 mm and 90 mm respectively. The thickness of the extensor pollicis longus at the proximal, middle and distal level of insertion were 1.25 mm, 0.76 mm and 0.55 mm respectively, whereas for the extensor pollicis brevis it was 1mm, 0.75 mm and 0.53 mm. The results obtained from this study may be helpful for the hand surgeons in the management of extensor tendon injuries of the thumb, its reconstructive procedures and in differential diagnosis of dorsal wrist pain.

Factors Affecting the Outcome of Medical Treatment in Cats with Obstructive Ureteral Stones Treated with Tamsulosin: 70 Cases (2018-2022).

Simple SummaryOther than surgical approaches the treatment options for feline ureterolithiasis are limited compared to those of human medicine. After various studies on ureteral muscle relaxation drugs, tamsulosin has been used as a treatment for distal ureteral stones in human medicine. However, the available clinical veterinary data on the efficacy of drugs that relax the ureter are limited. Thus, this study aimed to investigate the factors affecting the outcome of tamsulosin treatment for feline ureterolithiasis. With tamsulosin treatment, the ureteric stone passage was confirmed in 22 out of 70 cats, with a success rate of 31.43%. Negative factors with statistical significance for stone passage in this study were high baseline creatinine levels, female sex, proximal location of stones, and large diameter stones. The results of this study suggest that tamsulosin can be considered for the treatment of ureterolithiasis in cats with small distal ureteral stones. In addition, this study serves as an important reference for determining whether medical treatment of feline ureteral obstruction using tamsulosin can be attempted.The incidence of diseases associated with feline ureteral obstruction is increasing; however, non-surgical treatment options are limited. This study evaluated the outcome of medical treatment in cats with obstructive ureteral stones treated with tamsulosin and identified potential factors predicting spontaneous stone passage. We retrospectively reviewed 70 client-owned cats treated at the Western Referral Animal Medical Center, Seoul, Korea, from 2018 to 2022. All the cats had obstructive ureterolithiasis and were treated using tamsulosin. The baseline characteristics of the cats, stone diameter and location, and stone passage outcomes were analyzed. Stone passage occurred in 22 cats; the remaining 48 cats showed no change in stone locations. Sex, creatinine, and diameter and location of stones were potential risk factors associated with successful stone passage, but age, weight, and side of the stone were not. No serious adverse events related to tamsulosin treatment were observed. This is the first study to identify the risk factors predictive of the spontaneous stone passage of cats with obstructive ureterolithiasis after tamsulosin treatment. Tamsulosin could be an alternative treatment for ureteral obstruction in male cats with smaller distal ureteral stones and low baseline serum creatinine levels. These findings could help develop guidelines for treating feline ureterolithiasis.

Porcine Cortical Bone Lamina as a Predictable Technique for Guided Bone Regeneration: Histomorphometric and Radiographic Evaluation

The stability of bone regenerated through Guided Bone Regeneration (GBR) around implants is crucial for long-term success. In this case series, changes in marginal bone levels (MBL) around implants placed in a regenerated bone using heterologous cortical lamina technique were radiographically measured. In addition, bone samples were obtained and submitted to histological and histomorphometric analysis. Thirty implants were placed in regenerated bone sites 8 months after the regenerative surgery; in the same surgical stage, a hard tissue biopsy was taken using a trephine bur and submitted to histologic and histomorphometric analysis. Changes in the marginal bone level, mesial and distal to the implant shoulder, were measured between prosthetic loading and the last follow-up, 2 years later. No implants were lost, and all could be deemed successful at the last follow-up. Only a minimal mean variation in the position of the marginal bone level was observed, both at the mesial (0.11 ± 0.49 mm) and at the distal level (0.03 ± 0.19 mm). The bone lamina had been resorbed after 8 months, and new bone had developed in close connection to the biomaterial. The average percentage of newly formed bone was 28%, while only 10% of the samples were composed of residual biomaterial; bone marrow and connective tissue composed the remaining part of the samples. This regeneration technique allowed, thanks to the rigidity of the lamina, the regeneration of new bone, which is stable after the prosthetic load. Further studies are needed to compare this procedure with those adopting non-resorbable, titanium-supported membranes.

The evaluation of postoperative bowel dysfunction in Japanese patients with rectal cancer.

The present study assessed postoperative bowel dysfunction in Japanese patients with rectal cancer, including patients who underwent preoperative radiotherapy (RT). A total of 277 rectal cancer patients who underwent primary resection were included in the analyses. A questionnaire survey was administered using the low anterior resection syndrome (LARS) score and Wexner score. Scores were determined one year after rectal surgery or diverting ileostomy closure. The LARS score was categorized as minor LARS (21-29) and major LARS (30-42). The proportions of patients with minor and major LARS were significantly larger and Wexner scores significantly higher in patients with distal tumors and a lower anastomosis level than in those with proximal tumors and a higher anastomosis level. Among the patients with lower rectal cancer, the proportions with minor and major LARS were similar between those with and without preoperative RT. The Wexner scores in patients with preoperative RT were significantly higher than in patients without RT. A distal tumor location and lower anastomosis level were independent risk factors of major LARS in multivariate analyses. A distal tumor location, low anastomosis level, and preoperative RT might be associated with postoperative bowel dysfunction in rectal cancer patients.

Novel Dynamic Screw-Suture Stabilization System for Syndesmotic Repair Provides Better Anteroposterior Translation and Axial Tibiofibular Joint Stability: A Human Cadaveric Study

Category: Ankle; Basic Sciences/Biologics; Trauma Introduction/Purpose: The quest for optimal treatment of acute distal tibiofibular syndesmotic disruptions is still in full progress. Using suture-button repair devices is one of the dynamic stabilization options, however, they may not be always appropriate for stabilization of length-unstable syndesmotic injuries. Recently, a novel screw-suture repair system was developed to address such issues. The aim of this study was to investigate its performance in comparison to a suture-button stabilization of unstable syndesmotic injuries. Methods: Eight pairs of human cadaveric lower legs were CT scanned under 700 N single-leg axial loading in five foot positions - neutral, 15° external/internal rotation and 20° dorsi-/plantarflexion - in 3 different states: (1) pre-injured (intact); (2) injured, characterized by complete syndesmosis and deltoid ligaments cuts simulating pronation-eversion injury types III and IV as well as supination-eversion injury type IV according to Lauge-Hansen; (3) reconstructed, using a screw-suture (FIBULINK, Group 1) or a suture-button (TightRope, Group 2) implants for syndesmotic stabilization, placed 20 mm proximal to the tibia plafond/joint surface. Following, all specimens were: (1) biomechanically tested over 5000 cycles under combined 1400 N axial and +-15° torsional loading; (2) rescanned. Clear space (diastasis), anterior tibiofibular distance, talar dome angle and fibular shortening were measured radiologically from CT scans. Anteroposterior, axial, mediolateral and torsional movements at the distal tibiofibular joint level were evaluated biomechanically via motion tracking. Results: In each group clear space increased significantly after injury (p <= 0.004) and became significantly smaller in reconstructed compared with both pre-injured and injured states (p <= 0.041). In addition, after reconstruction it was significantly smaller in Group 1 compared to Group 2 (p < 0.001). Anteroposterior (AP) and axial movements were significantly smaller in Group 1 compared with Group 2 (p < 0.001, Figure). No further significant differences were identified/detected between the groups (p >= 0.113). Conclusion: Although both implant systems demonstrate ability for stabilization of unstable syndesmotic injuries, the screw- suture reconstruction provides better anteroposterior translation and axial stability of the tibiofibular joint and maintains it over time under dynamic loading. Therefore, it could be considered as a valid option for treatment of syndesmotic disruptions.

Upper limb movement during locomotion in patients with neurological disorders: a wearable-based approach

The contribution of upper limbs during walking is crucial in maintaining balance and stability: humans, in fact, swing each upper limb in phase with contra-lateral lower limb at their comfortable walking speed, with a ratio of 1:1 [1], thus counteracting the angular momentum, reducing the energy expenditure, and improving the overall gait efficiency [2,3]. In people who suffer from neurological disorders, like Multiple Sclerosis (MS) or Traumatic Brain Injury (TBI), upper limb function is often impaired, resulting in differences in arm swing frequency, amplitude, symmetry, as well as in the ratio between step and arm swing frequency, compared to healthy people [2]. Although it is known that a neurological rehabilitation program should focus on the recovery of a proper gait also emphasizing the contribution of upper limbs [1], few studies analyzed the contribution of the upper arms during locomotion in people with neurological disorders. The aim of this study is to explore a wearable sensor-based protocol for the assessment of the upper limb movement in patients with MS and TBI compared to healthy participants. Thirty-three patients suffering from MS (24 F; 49.8±9.3 y; EDSS 4.0±1.6), 8 patients suffering from TBI (2 F; 32.3±14.1 y; DGI 18.3±5.9), and 20 healthy adults (HC) (9 F; 37.0±19.9 y) were enrolled in this study (CE/PROG.700). Each participant performed a 10-meter Walking Test (10mWT) while wearing 5 synchronized inertial measurement units (IMUs) located at sternum, both wrists and distal tibiae level. Stride segmentation was performed using tibiae-mounted IMUs and the following parameters were estimated from wrist- and sternum-mounted IMUs [4]: arm oscillation frequency, peak and range of the angular velocity norm, as well as step to arm oscillation frequency ratio for the right (RW) and left (LW) wrists (freq, gyro peak, gyro range, Step-freq ratio). The range of the sternum cranio-caudal angular velocity was also obtained (sternum gyro range), together with a measure of symmetry (Symmetry Index [5]) between RW and LW angular velocity ranges. After checking for data normality, a one-way ANOVA was used to test for significant differences among MS, TBI, and HC. Post-hoc analysis was performed using Bonferroni-Holmes correction for multiple comparisons. Results are depicted in Fig. 1 (the larger the spider, the better the performance). Significant differences were found in frequency, symmetry, and angular velocity parameters among the MS, TBI, and HC. Patients with TBI seem to be characterized by a reduced performance with respect to MS, except for the step to arm swing ratio. The proposed assessment protocol demonstrates a potential clinical value in discriminating not only patients with neurological disorders from HC, but also patients with MS from TBI, who showed significant differences in terms of swing frequency, angular velocity range, and symmetry. This information could be useful in tailoring rehabilitation treatments involving the upper limbs during gait exercises [1]. Although in the present study, no significant difference was found among the three populations walking speed, the effect of the latter on the proposed metrics should be better investigated in further studies.

Effect of a new remnant-preserving technique with anatomical double-bundle anterior cruciate ligament reconstruction on MRI-based graft maturity: a comparison cohort study.

To investigate the effects of a new remnant-preserving double-bundle anterior cruciate ligament reconstruction (ACLR) technique, focused on avoiding remnant damage and preserving continuity of remnants, on graft maturity using magnetic resonance imaging (MRI). A total of 169 patients were divided into three groups: 41 in the preservation group, 70 in the resection group, and 58 in the absent group. In the preservation group, rather than passing the graft through the remnant tissue, the graft was reconstructed such that the anteromedial and posterolateral bundles sandwiched the remnant to avoid damage to the remnant and maintain its continuity. Based on 1-year postoperative MRI, the grafts were divided into three regions: distal, middle, and proximal. The signal/noise quotient (SNQ) of each region of interest was calculated to evaluate the signal intensity of the graft and was compared among the three groups. Additionally, to identify factors influencing graft maturity, a multiple regression analysis was performed with SNQ as the dependent variable and patient demographics, bone morphology, and surgical factors as independent variables. In a three-group comparison of mean SNQs, the distal region was 3.3 ± 3.4, 8.9 ± 8.3, and 9.0 ± 8.6 (p < 0.001), the middle region was 5.3 ± 3.7, 10.9 ± 11.1, and 11.3 ± 10.2 (p < 0.001), and the proximal region was 6.8 ± 4.5, 11.1 ± 8.8, and 11.7 ± 10.8 (p = 0.017), in order of the preservation, resection, and absent groups, respectively. That indicated that the remnant-preserving ACLR was more hypointense than ACLR with remnant resection or absent in all three regions. Multiple regression analysis showed that remnant preservation remained the relevant factor affecting SNQ of the graft at the distal and middle levels. The new remnant-preserving anatomic double-bundle ACLR had significantly better graft maturity, measured by SNQ on MRI, than the remnant resection and absent groups. The remnant procedure was the relevant factor affecting graft maturity. Level III.

Effects of Residual Arch Tears on Late Outcomes After Hemiarch Replacement for DeBakey I Dissection

BackgroundThis study evaluated the effect of residual arch tears on late reinterventions and arch dilatation after hemiarch replacement for patients with acute DeBakey type I aortic dissection. MethodsBetween January 1995 and October 2018, 160 consecutive patients who underwent hemiarch replacement for DeBakey type I dissection were retrospectively enrolled. They were divided into patients with (n = 73) and without (n = 87) residual arch tears. The arch tears group was subdivided into the proximal/middle arch (n = 26) and distal arch (n = 47) groups to evaluate arch growth rates according to the locations of residual arch tears. The endpoints were arch growth rate and late arch and composite events. ResultsThe arch diameter increased significantly over time in patients with residual arch tears (1.620 mm/y, P < .001). The increase occurred more rapidly when residual tears occurred at the distal arch than at the proximal/middle arch level (2.101 vs 1.001 mm/y). In the adjusted linear mixed model, residual arch tears or luminal communications at the distal arch level were significant factors associated with increases in the arch diameter over time. The 10-year freedom from late arch and composite event rate was significantly lower for patients with residual arch tears than for those without (82.4% vs 95.5%, P = .001; and 68.0% vs 89.3%, P = .002, respectively). ConclusionsResidual arch tears are significant factors associated with late arch dilatation and reinterventions, especially for patients with distal arch tears. Extensive arch replacement during the initial surgery to avoid residual arch tears may improve long-term outcomes.

Immediate implant placement with simultaneous bone augmentation versus delayed implant placement following alveolar ridge preservation: A clinical and radiographic study

ObjectiveThe present study aimed to evaluate the clinical and radiographic outcomes of immediate implant placement (IIP) with guided bone regeneration (GBR) as compared to delayed implant placement (DIP) following alveolar ridge preservation (ARP) and to identify the potential risk factors influencing these outcomes. MethodologyA total of 56 patients (IIP = 28 vs. DIP = 28) with class I or II bony defects received 56 implants were included. GBR procedure using Bio-Oss® bone substitute mixed with advanced platelet-rich fibrin (A-PRF) and covered by Bio-Gide® membrane and additional A-PRF membrane was performed either simultaneously with the IIP or earlier at the time of ARP in DIP. Clinical and 3-D radiographic analyses of bone level, thickness, and density were performed at three-time intervals (T1, immediately; T2, 6-7 months; and T3, 1.5 to 2 years post-implantation), corresponding to the neck, coronal, middle, and apex of implants. ResultsThe survival rate was 100% in both groups. IIP showed significant favorable outcomes regarding distal marginal bone level (anterior maxilla, T1-T3) and neck and coronal horizontal facial bone thickness (HFBT) (posterior maxilla, T1; and anterior maxilla, T1-T3, respectively) compared to DIP. However, DIP showed significant facial bone density at the neck and coronal parts in the anterior maxilla (T1) and the coronal part in the posterior maxilla (T3). The facial marginal bone level change was positively correlated with HFBT change (P = 0.007), which is negatively correlated with the secondary implant stability (P = 0.019). The implant region (anterior or posterior maxilla) was the only factor affecting on Implant stability quotient value (ISQ) and change in HFBT (P ˂ 0.05). ConclusionOverall, the IIP combined with GBR in the post-extraction sites with pre-implant class I or II bony defects had some favorable outcomes compared to DIP after ARP. However, the clinical outcomes, ISQ value, and changes in bone level, thickness, and density from T1-T3 were comparable.

Adjustable-Loop Cortical Suspensory Fixation Results in Greater Tibial Tunnel Widening Compared to Interference Screw Fixation in Primary Anterior Cruciate Ligament Reconstruction.

Background: Although the use of adjustable-loop suspensory fixation has increased in recent years, the influence of the shortcomings of suspensory fixation, such as the bungee-cord or windshield-wiper effects, on tunnel widening remains to be clarified. Hypothesis/Purpose: The purpose of this study was to compare adjustable-loop femoral cortical suspensory fixation and interference screw fixation in terms of tunnel widening and clinical outcomes after anterior cruciate ligament reconstruction (ACLR). We hypothesized that tunnel widening in the adjustable-loop femoral cortical suspensory fixation (AL) group would be comparable to that in the interference screw fixation (IF) group. Methods: This study evaluated patients who underwent primary ACLR at our institution between March 2015 and June 2019. The femoral and tibial tunnel diameters were measured using plain radiographs in the immediate postoperative period and 2 years after ACLR. Tunnel widening and clinical outcomes (Lysholm score, 2000 International Knee Documentation Committee subjective score, and Tegner activity level) were compared between the two groups. Results: There were 48 patients (mean age, 29.8 ± 12.0 years) in the AL group and 44 patients (mean age, 26.0 ± 9.5 years) in the IF group. Tunnel widening was significantly greater in the AL group than that in the IF group at the tibia anteroposterior (AP) middle (2.03 mm vs. 1.32 mm, p = 0.017), tibia AP distal (1.52 mm vs. 0.84 mm, p = 0.012), tibia lateral proximal (1.85 mm vs. 1.00 mm, p = 0.001), tibia lateral middle (2.36 mm vs. 1.03 mm, p < 0.001), and tibia lateral distal (2.34 mm vs. 0.85 mm, p < 0.001) levels. There were no significant differences between the two groups with respect to femoral tunnel widening and clinical outcomes. Conclusions: Tibial tunnel widening was significantly greater in the AL group than in the IF group at 2 years after primary ACLR. However, the clinical outcomes in the two groups were comparable at 2 years.

Editorial: The Problem with Abbreviations and Acronyms

Editorial: The Problem with Abbreviations and Acronyms

Tiempos de activación muscular frente a una desestabilización en pacientes con enfermedad de Parkinson en etapas iniciales

ObjectivesParkinson's disease (PD) generates a high incidence of falls, however, there is little evidence of instabilities in the initial stages. This investigation sought to compare the muscle activation times in patients with initial PD against a postural disturbance vs. a control group. Materials and methodsThe electromyographic activity (EMG) of 10 patients with PD in early stages (61.3 ±3.8 years) and a control group of 10 adults (62.2 ±3.0 year) was evaluated. The participants were subjected to a surface disturbance, which generated a stabilization response. The test was performed under 2conditions: eyes open (OA) v/s eyes closed (OC). Trunk (spinal erector) and lower extremity (soleus, tibialis anterior, femoral biceps, femoral rectus, adductor magnus, gluteus medius) muscle activation time was analyzed using surface EMG. ResultsThe PD group showed faster response times compared to the control group in the soleus muscle in OC (P=.04). This same muscle showed differences when comparing OA vs. OC only in the PD group (P=.04), showing a shorter response time in the OC condition. When comparing the spinal erector muscle, the PD group showed slower response times in the OA (P=.02) and OC (P=.04) conditions compared to the control group. ConclusionsMuscle activation times show that people with PD respond slower in the trunk muscles, while activation times decrease at the distal level. In the early stages, the slower responses at the trunk level could explain the onset of instability postural in these patients.

P23. Inline axial forces associated with implantation of ALIF interbody devices with integrated supplemental fixation

<h3>BACKGROUND CONTEXT</h3> Anterior lumbar interbody fusion (ALIF) allows for an optimal sized interboy device while providing correction for lumbar lordosis, restoration of disc height and indirect decompression. Spinal interbody devices with integrated fixation through blades, screws or other supplemental anchoring components mitigate the need for supplemental instrumentation, thus reducing OR time and preserving the stability of the functional spinal unit. Unfortunately, interbody devices have failed at the bone implant interface resulting in complications including implant migration and expulsion. Gaining a better understanding of the biomechanics associated with interbody placement may help to prevent these complications in the future. The aim of present study is to determine the magnitude and effect of axial forces during the deployment of an interbody device with supplemental integrated fixation. <h3>PURPOSE</h3> To understand the axial loading imparted to the functional spinal unit during lumbar interbody fusion surgery. <h3>STUDY DESIGN/SETTING</h3> Biomechanical axial load mesaurement in cadaveric functional spinal units during lumbar disc preparation and spinal interbody device implant procedures. <h3>METHODS</h3> Cadaveric functional spinal units, levels L2-L3, L3-L4, L4-L5, and L5-S1, were decorticated to the osteoligamentous structures. Posterior elements were removed to allow for MicroCT imaging of each specimen at a voxel size of 27 micron before and after instrumentation. A custom test fixture was used to apply 50N compressive force to stabilize the specimen and also record inline axial forces associated with the deployment of anchor plates during instrumentation procedures. A Chatillon DFS II force gauge was used to record axial forces during implantation of ENZA 1.0 and ENZA 2.0 interbody devices. Axial forces resulting from implant trialing, device insertion and anchor deployment were recorded. MicroCT scans were repeated to allow for quantification of damage to bony structures as a result of implantation procedures. <h3>RESULTS</h3> L2-L3 and L3-L4 force outputs are similar for both insertion, 218.82 N, 219.89 N, and deployment forces, 34.58 N, 44.88 N respectively. Insertion forces throughout all spinal levels were larger than both deployment and removal forces. Insertion forces were larger in the proximal levels, 218.82 N, 219.89 N, when compared to the distal levels, 178.96 N, 113.76 N. However, deployment force was larger in the distal levels, 99.03 N, 77.76 N, when compared to proximal 34.58 N, 44.88 N. <h3>CONCLUSIONS</h3> As evidence mounts for the cost-effectiveness of standalone cages with integrated supplemental fixation, it is imperative that design requirements of these devices continue to improve. Previous studies have shown that the vertebral endplate is susceptible to fracture under compressive loading, with the weakest area of the vertebrae being the center region. In 2001, Hasegawa et al showed a cylindrical-shaped implant caused endplate fracture between 510N and 1335N and that implant size is inversely related to the force required to cause fracture. Endplate fracture is difficult to detect with standard imaging modalities and leaves the patient vulnerable to implant subsidence and reduces segmental stability as a result of changes in load transfer. Furthermore, endplate failure may be a contributor to low back pain, further reducing the chance of a successful outcome. Our study showed interbody devices with integrated fixation plates could safely be inserted and deployed in the disc space without causing endplate fracture. The implant-endplate interface should be investigated in greater detail to allow for design of standalone interbody devices which do not cause unintended distraction or worse, damage to the vertebrae. <h3>FDA DEVICE/DRUG STATUS</h3> ENZA Lumbar Interbody Fusion Device (Approved for this indication).

84. Does interbody fusion change ASD in the disc next to the fusion? 10 years of MRI follow-up on a randomized controlled study

<h3>BACKGROUND CONTEXT</h3> Due to the increasing number of spinal procedures performed worldwide, adjacent degenerative disease has become a new focus area. Whether adjacent segment disease is a matter of normal degenerative development in the disc over time or a result of increased stiffness and stress due to the fusion is still debated. Nowadays TLIF is the most widely used interbody fusion method. The use of interbody fusion has been claimed to reduce degenerative changes in the spared free disc over time due to better sagittal balance and restoration of the lost lumbar lordosis. <h3>PURPOSE</h3> To compare degenerative changes on MRI between PLF and TLIF 10 years postsurgery in an RCT cohort. <h3>STUDY DESIGN/SETTING</h3> Randomized clinical trial (RCT). Long-term follow-up. <h3>PATIENT SAMPLE</h3> Out of a primary cohort of 100 patients included in a prospective RCT between inter-body fusion and instrumented posterolateral fusion, 79 were available for follow-up 10 years after inclusion in the RCT. Patients were seen in the outpatient clinic and offered MRI at long-term follow-up. <h3>OUTCOME MEASURES</h3> Changes over time in Modic, Pfirmann, Schizas, and Fardon and Milette. <h3>METHODS</h3> All MRI were classified according to degree of Modic changes, Pfirmann classification, Schizas classification, and Fardon and Milette classification in order to show the degree of degeneration of the discs above and below the fusion. The grading was done by independent observers without any contact to the patient. In patients who underwent secondary surgery, the immediately previous MRI was used and the degenerative changes measured according to the above-mentioned classifications. <h3>RESULTS</h3> The groups were equal regarding sex, age, diagnosis and number operated levels. The follow-up was 9.6 years. The Modic change found at the first upper level was none in (85%/68%), mostly grade 2 (12%TLIF/26%PLF). There was no significant difference between the two groups p=0.274. Nearly all patients did not show any sign of treatment needs regarding spinal stenosis according to Schizas classification 92%/92%; only 8/8% had type C and D at the first proximal level 9.6 years after surgery. Interestingly, the amount of spinal stenosis grade C and D was higher at second proximal disc. No difference between groups could be detected p = 0.930 & p = 0.500. The Pfirmann grading at the first proximal level did not show any difference between groups p = 0.952. <h3>CONCLUSIONS</h3> In an RCT, the use of interbody fusion (TLIF) does not reduce the degenerative changes in the first proximal disc next to the fusion in a long-term observational study period in comparison to a normal posterolateral instrumented fusion (PLF). Thus, degenerative changes in the first proximal level are not influenced by intercorporal devices. The incidence of spinal stenosis grade C and D, 10 years after lumbar fusion surgery are 8% at first proximal disc, 13 % at second proximal disc and 8% at first distal level. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

P48. Mechanisms of lumbar spine ‘flattening’ in adult spinal deformity: defining changes in shape that occur relative to a normative population

<h3>BACKGROUND CONTEXT</h3> Loss of lumbar curvature is often expressed as an angular regional loss. Previous work comparing adult spinal deformity (ASD) lumbar alignment to their age-and-PI adjusted normative value demonstrated that, contrary to general belief, a large proportion of the curvature is lost proximally (L1-L4). This study is a follow-up looking not only at regional angles, but also at the spinal contour collectively. <h3>PURPOSE</h3> Investigate the difference of lumbar shape between ASD and age-and-PI adjusted normative values. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of an ASD registry. <h3>PATIENT SAMPLE</h3> A total of 119 asymptomatic volunteers and 362 ASD patients. <h3>OUTCOME MEASURES</h3> Sagittal alignment of the lumbar and thoracolumbar spine measures using vertebra pelvic angle from L5 to T10. <h3>METHODS</h3> Before studying ASD patients, 119 asymptomatic volunteers with full-body, free-standing radiographs were used to identify age-and-PI models of each vertebra pelvic angle (VPA) from L5 to T10, a validated methodology characterizing the detailed shape of the spine. Our study cohort was a registry of surgical primary ASD patients without coronal malalignment (SRS-Schwab Type=N). The formulas developed in the asymptomatic population were applied to the ASD group to calculate an age-and-PI normative spine shape for each patient. Loss of lumbar lordosis was defined as the offset between age-and-PI normative value and pre-operative spino-pelvic alignment. Patients were stratified into four groups by the amount of lordosis lost, ranging from "no loss" to "30° loss." Paired t-tests were performed to compare actual and normative VPA shapes within each group. <h3>RESULTS</h3> Out of 1,495 patients enrolled in this registry, 453 were primary cases, and 653 were categorized as a Schwab type N, leading to a cohort of 362 patients (age=64.4±13, 57.1% F). Pre-operative alignment demonstrated a large variability with a mean PI-LL of 15°±21, distal LL=31°±15, and PI=55°±13. Compared to their age-and-PI normative values, ASD patients demonstrated a significant lordosis loss of 17°±19 with the following distribution: 14.1% no loss (mean: 0.1±2.3), 22.9% with 10° loss (mean: 9.9±2.9), 22.1% with 20° loss (mean: 20.0±2.8), and 29.3% with 30° loss (mean:33.8±6.0). Comparison of the VPAs (and therefore the shape) between each LL group and the normative shape demonstrated that the "no loss" patients had a lumbar spine slightly anterior to the normative shape from L4 to T10 (VPA difference of 2°). The shape of the "small deformity" group (10°) superimposed on the normative one from L5 to L2 (VPA with p>0.1) and became anterior at the L1 level. As the lordosis loss increased, the offset between ASD and normative shapes began to propagate to the distal levels and became significant extending caudally to the L3 level for the "20° loss" group and further down to L4 for the more severe group. <h3>CONCLUSIONS</h3> As the deformity progresses and the loss of lordosis increases, the difference between ASD shape and normative shape happens first proximally and then progresses incrementally caudally with increasing deformity. Understanding the spinal contour and the location of this loss, in addition to regional parameters, may be key to achieving a sustainable correction by identifying optimal and personalized post-operative shape. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Fusion Mass Screws in Revision Spinal Deformity Surgery: A Simple and Safe Alternative Fixation.

Revision spinal deformity surgery has a high rate of complications. Fixation may be challenging due to altered anatomy. Screws through a fusion mass are an alternative to pedicle screw fixation. The purpose of this retrospective study was to further elucidate the safety and efficacy of fusion mass screws (FMSs) in revision spinal deformity surgery. Retrospective case series. Fifteen freehand FMSs were placed in 6 patients with adult spinal deformity between 2016 and 2018 by the senior author. FMSs were combined with pedicle screws, at times at the same level. FMSs were used to save distal levels from fusion, assist in closing a 3-column osteotomy and provide additional fixation in cases of severe instability. Computed tomography (CT) was used to assess bone mineral density (BMD) and thickness of each fusion mass preoperatively along with accuracy of FMS placement postoperatively. The mean BMD of the fusion mass was 397 Hounsfield units (HU; range: 156-628 HU). The mean AP thickness of the fusion mass was 15.5 ± 4.8 mm (range: 8.6-24.4 mm). The mean FMS length was 35.3 ± 5.5 mm (range: 25-40 mm). There was no evidence of FMS loosening, breakage, or pseudarthrosis at latest follow-up (mean: 2.2 years, range: 1.4-3.1 years). No neurologic deficits were observed. 1/15 screws had a low-grade breach into the canal (<2 mm). No patients required revision surgery. FMSs may be used to augment fixation in revision spinal deformity cases when pedicle screw placement may be challenging. FMSs may also provide an additional anchor at levels with pedicular fixation.