Foramen Height Research Articles

Anterior lumbar interbody fusion (ALIF): biometrical results and own experiences

Lumbar fusion is a mainstay in the treatment of low back pain resulting from degenerative disc disease. Anterior lumbar interbody fusion (ALIF) has become a reasonable treatment technique to achieve indirect foraminal decompression with high fusion rates. The aim of the study was to analyse the biometrical parameters of the lumbar spine and the clinical outcome. The medical records of 51 patients treated with ALIF between 2012 and 2016 were retrospectively reviewed. Anterior and posterior disc height (DH), lumbar lordosis (LL), local disc angle (LDA) and foraminal dimensions were obtained on pre- and postoperative plain radiographs and computed tomography scans using ImageJ and Surgimap software according to the pedicle–pedicle technique. To evaluate the interbody fusion status on the last follow-up CT scans, we used Bridwell criteria. Preoperative and 12 months postoperative Oswestry Disability Index (ODI) scores were determined for all patients. The average length of hospitalisation was 4 days. Most of the patients had degenerative disc disease with foraminal stenosis. Five patients had early complications like paresthesia of lower limbs, sympathetic dysfunction or wound infections, but there were no major complications. Statistically significant (P < .01) improvement was observed in foraminal dimensions (area = 49%, height = 33% and width = 19%), anterior DH (49%), posterior DH (69%), LDA (47%) and LL (17.5%). Posterior DH correlated significantly with foramen height improvement. Radiographic evidence of fusion according to the modified Bridwell criteria (grade I and grade II) was observed in 96% (49/51) of the patients in the last CT of the lumbar spine. We also observed significant improvement in functional recovery in 94% of patients. The mini-open ALIF approach is a reasonable alternative to the more extensive posterior approaches. ALIF significantly restores the height of the intervertebral disc, indirectly increases foraminal dimensions, increases lordosis angle with significant short and long-term pain relief and functional recovery.

Effect of Cage in Radiological Differences between Direct and Oblique Lateral Interbody Fusion Techniques.

ObjectiveFew studies have reported direct comparative data of lumbar spine angles between direct lateral interbody fusion (DLIF) and oblique lateral interbody fusion (OLIF). The purpose of this study was to investigate the clinical and radiological outcomes of DLIF and OLIF, and determine influential factors. MethodsThe same surgeon performed DLIF from May 2011 to August 2014 (n=201) and OLIF from September 2014 to September 2016 (n=142). Radiological parameters, cage height, cage angle (CA), cage width (CW), and cage location were assessed. We checked the cage location as the distance (mm) from the anterior margin of the disc space to the anterior metallic indicator of the cage in lateral images. ResultsThere were significant differences in intervertebral foramen height (FH; 22.0±2.4 vs. 21.0±2.1 mm, p<0.001) and sagittal disc angle (SDA; 8.7±3.3 vs. 11.3±3.2˚, p<0.001) between the DLIF and OLIF groups at 7 days postoperatively. CA (9.6±3.0 vs. 8.1±2.9˚, p<0.001) and CW (21.2±1.6 vs. 19.2±1.9 mm, p<0.001) were significantly larger in the OLIF group compared to the DLIF group. The cage location of the OLIF group was significantly more anterior than the DLIF group (6.7±3.0 vs. 9.1±3.6 mm, p<0.001). Cage subsidence at 1 year postoperatively was significantly worse in the DLIF group compared to the OLIF group (1.0±1.5 vs. 0.4±1.1 mm, p=0.001). Cage location was significantly correlated with postoperative FH (β=0.273, p<0.001) and postoperative SDA (β=-0.358, p<0.001). CA was significantly correlated with postoperative FH (β=-0.139, p=0.044) and postoperative SDA (β=0.236, p=0.001). Cage location (β=0.293, p<0.001) and CW (β=-0.225, p<0.001) were significantly correlated with cage subsidence. ConclusionThe cage location, CA, and CW seem to be important factors which result in the different-radiological outcomes between DLIF and OLIF.

Correction of Spondylolisthesis by Lateral Lumbar Interbody Fusion Compared with Transforaminal Lumbar Interbody Fusion at L4-5.

ObjectiveIn an aging society, the number of patients with symptomatic degenerative spondylolisthesis (DS) is increasing and there is an emerging need for fusion surgery. However, few studies have compared transforaminal lumbar interbody fusion (TLIF) and lateral lumbar interbody fusion (LLIF) for the treatment of patients with DS. The purpose of this study was to investigate the clinical and radiological outcomes between TLIF and LLIF in DS. MethodsWe enrolled patients with symptomatic DS at L4–5 who underwent TLIF with open pedicle screw fixation (TLIF group, n=41) or minimally invasive LLIF with percutaneous pedicle screw fixation (LLIF group, n=39) and were followed-up for more than one year. Clinical (visual analog scale and Oswestry disability index) and radiological outcomes (spondylolisthesis rate, segmental sagittal angle [SSA], mean disc height [MDH], intervertebral foramen height [FH], cage subsidence, and fusion rate) were assessed. And we assessed the changes in radiological parameters between the postoperative and the last follow-up periods. ResultsPreoperative radiological parameters were not significantly different between the two groups. LLIF was significantly superior to TLIF in immediate postoperative radiological results, including reduction of spondylolisthesis rate (3.8% and 7.2%), increase in MDH (13.9 mm and 10.3 mm) and FH (21.9 mm and 19.4 mm), and correction of SSA (18.9° and 15.6°) (p<0.01), and the changes were more stable from the postoperative period to the last follow-up (p<0.01). Cage subsidence was observed significantly less in LLIF (n=6) than TLIF (n=21). Fusion rate was not different between the two groups. The clinical outcomes did not differ significantly at any time point between the two groups. Complications were not statistically significant. However, TLIF showed chronic mechanical problems with screw loosening in four patients and LLIF showed temporary symptoms associated with the surgical approach, such as psoas and ileus muscle symptoms in three and two cases, respectively. ConclusionLLIF was more effective than TLIF for spondylolisthesis reduction, likely due to the higher profile cage and ligamentotactic effect. In addition, LLIF showed mechanical stability of the reduction level by using a cage with a larger footprint. Therefore, LLIF should be considered a surgical option before TLIF for patients with unstable DS.

Application of New Allogeneic Lumbar Fusion Cage (Biocage) in Single-Segment Lumbar Degenerative Disease: A Prospective Controlled Study with Follow-Up for ≥2 Years

We evaluated the clinical efficacy of the Biocage in lumbar fusion surgery and its safety and effectiveness. A total of 431 patients with single-segment lumbar degenerative disease diagnosed from January 2013 to December 2016 were considered for the present prospective, nonrandomized, and controlled study; 52 patient met the exclusion criteria and were excluded. The patients were divided into 2 groups according to their cage choice: Biocage (n= 206) and polyether ether ketone (PEEK) cage (n= 173). The patients were followed up for 24-48 months (average, 32). The operative time, blood loss, hospitalization duration, mean intervertebral fusion segment height, height of intervertebral foramen, fusion time, fusion rate, internal fixation failure rate, visual analog scale score, and Oswestry disability index were compared between the 2 groups. All the patients underwent surgery successfully. No significant differences were found in gender, age, clinical diagnosis, lesion segment, operative time, blood loss, visual analog scale score, or Oswestry disability index between the 2 groups. No significant differences were found in the fusion rate; however, the Biocage group had a greater fusion rate and shorter fusion time than the PEEK group. During follow-up, the mean intervertebral height recovered significantly in the Biocage group compared with the PPEK group (P < 0.05). The height of the intervertebral foramen was significantly different between the 2 groups, and recovery was better in the Biocage group (P<0.05). The Cobb angle of fusion segment in both groups improved significantly postoperatively compared with preoperatively (P < 0.05). The improvement in Cobb angle was significantly different between the 2 groups (P < 0.05). The Biocage has excellent clinical efficacy in the treatment of lumbar degenerative disease. Although the Biocage achieved good therapeutic effects, it did not show obvious advantages compared with the PEEK cage. Therefore, the Biocage can only be used as a choice of bone graft materials for lumbar fusion surgery and should not completely replace the PEEK cage.

Clinical and radiologic outcomes of single-level direct lateral lumbar interbody fusion in patients with osteopenia

ObjectiveSubsidence of the interbody graft into the vertebral bodies is one of the major complications of direct lateral interbody fusion (DLIF), resulting in pseudoarthrosis and severe pain. Low bone mineral density (BMD) has been known to increase the risk of subsidence. This study aims to determine whether or not the osteopenia should influence the surgical results in DLIF surgery. MethodsWe retrospectively reviewed the data collected prospectively on all patients who underwent single-level DLIF at our institution. A total of 84 patients were included in this study, comprised of 41 in the osteopenia group and 43 in the normal BMD group. The clinical and radiologic characteristics were compared at preoperative and postoperative 1 and 2 years. ResultsAt postoperative two years, there was a statistically significant difference in disc height and intervertebral foramen height at index level between the two groups (p = 0.039, 0.044, respectively), but there was no significant difference in total lumbar lordosis (p = 0.179). At 24-month postoperative, 92.7% of the osteopenia group and 95.3% of the normal BMD group were solidly fused (p = 0.672). All postoperative clinical scores (VAS back pain, VAS leg pain, and ODI) improved similarly in both groups without significant difference. The overall incidence of cage subsidence with >3 mm was 17.1% in the osteopenia group and 9.3% in the normal BMD group (p = 0.345). ConclusionsPatients with osteopenia who undergo single-level DLIF combined with posterior fixation exhibited comparable clinical and radiological outcomes as patients with normal BMD.

Radiographic evaluation of the impact of cage position on indirect neural decompression in crenel lateral interbody fusion

Objective To explore the impact of cage position on indirect decompression and cage subsidence in crenel lateral interbody fusion (CLIF). Methods Retrospectively, 18 mens and 16 womens with a mean age of 63.98±5.99 years (range: 52-75 years) who underwent CLIF for lumbar stenosis by our surgical group during November 2016 and Feburary 2018 were reviewed. Sixty-two segments were included for radiographic evaluation. Endplates thickness was measured using high resolution computed tomography. By image processing, endplate thickness was measured at 10 equally distributed points on the mid-sagittal and mid-coronal planes, and two further planes were measured at an angle of 45° to both the first and second planes. Contour plots representing an isoline of endplate thickness was drawn based on those data. The cages were classified into anterior group and medium-posterior group. Radiographic evaluation included segmental angle, anterior and posterior disk heights, intervertebral foramen heights, and cross-sectional area of the spinal canal. To assess the factors affecting the postoperative segmental angle and cross-sectional area of the spinal canal, univariate and multivariate analysis were performed using the regression analysis model. Cage subsidence was recorded at the last follow-up. Results The mean follow-up time of those patients were 10.88±3.73 months (range: 6-18 months). At each spot, the mean thickness was significantly greater for the cranial endplate of disc than the caudal endplate. Contour plots show more areas of thick bony endplates in the anterior and anterolateral part of the endplate than the lateral and posterior part, especially for the cranial endplate. The cage was placed in the anterior area for 19 levels and medium-posterior for 41 levels. The mean increase of anterior disk height was 3.38±3.38 mm in anterior group and 1.83±3.08 mm in medium-posterior group(P=0.04). The mean increase of segmental angle was 2.93°±3.47°in anterior group and 0.73°±3.60° in medium-posterior group(P=0.04). No significant difference was found with mean increase of posterior disk height, mean increase of intervertebral foramen heights, as well as increase ratios of cross-sectional area of the spinal canal between groups. Multivariate analysis showed that the increase of segmental angle was affected by cage position (β=1.24, P=0.03), but the increase ratios of cross-sectional area of the spinal canal was not affected. The subsidence rate of anterior group was 15.79% (3/19) and medium-posterior group was 24.39% (10/41), which was not significantly different (χ2=0.56, P=0.45). Conclusion There are more areas with thick bony endplates in the anterior and anterolateral parts of the lumbar endplate than the lateral and posterior parts. The cage position at the anterior 1/3 of disk space is better for achieving the restoration of the segmental angle and having lower subsidence rate, without compromising the indirect neural decompression in crenel lateral interbody fusion. Key words: Lumbar vertebrae; Spinal fusion; Internal fixators; Postoperative complications

Case control study of unilateral and bilateral intervertebral space release in the treatment of lower lumbar spondylolisthesis

To analyze the clinical efficacy of unilateral and bilateral intervertebral space release in the treatment of lower lumbar spondylolisthesis. The clinical data of 41 patients with lumbar spondylolisthesis treated by surgery from October 2012 and May 2016 were retrospcetive analyzed. The patients were divided into two groups, 18 cases were enrolled in unilateral intervertebral release group, there were 7 males and 11 females, aged from 47 to 75 years old with an average of (59.3±6.4) years; according to Meyerding classification, 9 cases of I degree, 7 cases of II degree, 2 cases of III degree. And 23 cases were bilateral release group, there were 11 males and 12 females, aged from 51 to 76 years old with an average of (58.2±5.7) years; according to Meyerding classification, 11 cases of I degree, 10 cases of II degree, 2 cases of III degree. The operation time, intraoperative blood loss, bone graft fusion rate of the patients were recorded in the patients. Pre- and post-operative back and leg pain were evaluated by visual analogue scale (VAS) between two groups. The slip rate, slip angle, posterior height of intervertebral space, height of intervertebral foramen, distance of anterior and posterior displacement of vertex of intervertebral foramen were measured on X-ray and CT. And the above radiographic data were analyzed by intra-group or inter-group. All the patients were followed up from 9 to 24 months with an average of 12 months. The entire 41 patient obtained bone fusion at 12 months after operation. There was no statistical significance in VAS at 12 months after operation, intraoperative blood loss and operation time between two groups(P>0.05). There were statistical significance in sliding angle, posterior height of intervertebral space, height of intervertebral foramen, distance of anterior and posterior displacement of vertex of intervertebral foramen of all patients before and after operation(P<0.05). There was no statistical significance in spondylolisthesis rate in unilateral release group between pre- and post-operative(P>0.05), but there was significant difference in bilateral release group. There was statistical significance in postoperative slip angle, posterior height of intervertebral space, distance of anterior and posterior displacement of vertex of intervertebral foramen between two groups(P=0.001, 0.045, 0.001). The height of intervertebral foramen increased and the slippage rate decreased in both groups after operation, but there was no significant difference between two groups(P=0.248). Unilateral and bilateral intervertebral space release for the treatment of lumbar spondylolisthesis can obviously reduce the rate of spondylolisthesis, restore foraminal height and achieve better clinical efficacy. Bilateral release group can better restore the slip angle, increase posterior height of intervertebral space, reduce the distance of anterior and posterior displacement of vertex of intervertebral foramen. Especially for grade II or above degree of slippage is more appropriate.

Facet Joint Osteoarthritis Affects Spinal Segmental Motion in Degenerative Spondylolisthesis

This is a retrospective clinical case series (case-control study). To clarify the influence of facet joint osteoarthritis (FJOA) on the pathology of degenerative spondylolisthesis (DS) using in vivo 3-dimensional image analysis. There are no radical treatments to prevent progression of DS in patients with lumbar spinal canal stenosis associated with DS. Therefore, an effective treatment method based on the pathology of DS should be developed. In total, 50 patients with lumbar spinal canal stenosis involving L4/5 who underwent dynamic computed tomography were divided into 2 groups: with DS [spondylolisthesis (Sp) group; 12 male, 14 female; mean age, 74 y]; and without DS (non-Sp group; 15 male, 9 female; mean age, 70 y). Degeneration of the intervertebral disk and FJOA at L4/5 were evaluated using magnetic resonance imaging. Disk and intervertebral foramen heights, the distance between the craniocaudal edges of the facet joint, and the interspinous distance were measured on dynamic computed tomographic images. Also, in vivo 3-dimensional segmental motion was evaluated using the volume merge method. There were no significant differences in degenerative findings for the intervertebral disk; however, progressive FJOA was detected in the Sp group. Dynamic changes in the distance between the craniocaudal edges of the facet joints were significantly larger in the Sp group. In this study, progressive FJOA and larger segmental motion in the distance between the craniocaudal edges of the facet joints were found in the Sp group. We clarified for the first time that DS involves ligament laxity due to FJOA that affects spinal segmental motion in vivo. We consider that a treatment method based on FJOA would be useful for treating patients with DS. Level IV.

Anatomical analysis of the human ligamentum flavum in the thoracic spine: Clinical implications for posterior thoracic spinal surgery

BackgroundKnowledge of the ligamentum flavum anatomy is important for posterior spinal surgery. However, only a few studies have evaluated the relationship between the thoracic ligamentum flavum and its surrounding structures. This study aimed to clarify the anatomy of the thoracic ligamentum flavum. MethodsThe entire spines from 20 human embalmed cadavers were harvested in an en bloc fashion. All pedicles were vertically cut using a thread bone saw, and the ligamentum flavum from T1-T2 to T12-L1 was painted using a contrast agent containing an iron powder. Computed tomography was performed, and the ligamentum flavum shape (width and height) and its relationship with the spinal bony structures (lamina and foramen height percentage covered by the ligamentum flavum) were analyzed using a three-dimensional analyzing software. ResultsThe thoracic ligamentum flavum height and width gradually increased from T1-T2 to T12-L1. The caudal lamina height ventrally covered by the ligamentum flavum also increased gradually from the upper (T1-T2: 31.7%) to the lower levels (T12-L1: 41.7%); however, the cranial lamina height dorsally covered by the ligamentum flavum decreased from the upper (12.6%) to the lower levels (4.3%). The neural foramen was covered by the ligamentum flavum in all thoracic spines, except for T1-T2. Between T2-T3 and T12-L1, approximately 50% of the cranial part of the foramens was covered by the ligamentum flavum; however, the caudal part was not covered. ConclusionsThis study using contrasted ligamentum flavum and reconstructed CT provided information on the thoracic ligamentum flavum shape and its relationship with the bony structures. The ventral ligamentum flavum coverage of the cranial lamina increase from cranial to caudal, and the cranial half of the neural foramen is covered by the ligamentum flavum below T2-T3 but not in T1-T2. These findings would help spine surgeons to design and perform safe and adequate posterior thoracic spinal surgeries.

Effect of range of motion (ROM) for pedicle-screw fixation on lumbar spine with rigid and semi-rigid rod materials: A finite element study

This study aims to understand the biomechanical effect of pedicle-screw fixation with different implant materials on lumbar spine. FE method is used to develop three-dimensional model of lumbar spine (L1-S). Three level pedicle-screw-rod is attached to the model with two different rods: Stainless Steel (SS) and poly-ether-ether-ketone (PEEK). The implanted models along with intact models are simulated for different physiological conditions such as axial rotation, lateral bending and flexion-extension under ± 6, 8 and 10 Nm moment with 500 N compressive loads. The spinal biomechanics found sensitive to the elastic modulus of the rod material. In case of pedicle screw fixation with SS, the ROM is very less (1.3° for extension and 2.88° for flexion) as compared to natural model. For PEEK rod, ROM is increased 3 to 4 times for axial rotation, 4 to 7 times for lateral bending and 1.8 to 2 times for flexion-extension. SS rods share more load and generate less stress on vertebrae compared and PEEK rods. For pedicle screw fixation, the foramen height does not vary significantly with variation of load and rod materials. SS rods resist the ROM on the implanted region affecting the kinematics of the spine undesirably. The ROM may be improved to some extent by using lower stiffness rod materials like PEEK. However pedicle screw fixation device prevents reducing inter-vertebral foramen height and foramen area, without affected by material stiffness.

CT assisted goat lumbar vertebrae anatomical measurement and comparison with human lumbar vertebrae

To study the anatomical measurement of goat lumbar vertebrae and to compare with human lumbar vertebrae, so as to build the foundation for establishing animal models of lumbar prosthesis. The anatomical parameters of the vertebral body, pedicle and intervertebral disc in the fresh lumbar vertebrae of Boer goat and the lumbar vertebrae of healthy adults were collected by computer aided software Mimics16.0, and the anatomical characteristics of the two lumbar vertebrae were compared with the statistical software. The anterior vertebral body height(VBHa) of goat lumbar was less than the middle vertebral body height(VBHm), which was less than the posterior vertebral body height(VBHp), and the maximum values were (38.7±2.9), (40.1±2.6) and (40.7±2.7) mm respectively. Its endplate width was greater than its depth, with the whole shaped like a heart or a kidney. The cranial endplate of goats was convex while the caudal endplate was depressed and the depression was small, with a maximum value of (1.6±0.6) mm. The pedicle height of goats increased from L₁1 to L̀ with the maximum of (30.5±1.9) mm; its pedicle width and angle increased firstly and then decreased with the increase of vertebra level and the minimum values were (6.7±0.4) mm and(45.9±2.6)° respectively. The anterior intervertebral disc height was larger than the middle which was larger than the posterior and all varied slightly with the changes of intervertebral spaces; the height and width of intervertebral foramen separately waved at (12.9±0.3) to (14.3±1.0) mm and (5.7±1.0) to (6.7±0.9) mm. The comparative results showed that the vertebral body height, pedicle height and angle of goats were greater than those of humans (P<0.05) while the width and depth of the endplate, the intervertebral disc height, and etc. were significantly smaller than those of humans (P<0.05). In addition, some structures, such as the height of pedicle and intervertebral disc, also showed different changing laws with the increase of vertebra level. Although there are similarities in goat lumbar spine in some aspects, such as endplate and foramen foramen, there are still many differences in many aspects. Understanding the anatomical characteristics of goat lumbar vertebrae and the difference between goat and human is of great guiding significance for the research of goat prosthesis and related technology.

Assessment of pelvic tilt in anteroposterior radiographs by means of tilt ratios

In anteposterior (AP) radiographs, cup position in total hip arthroplasty and acetabular anatomy in hip-preserving surgery are highly influenced by pelvic tilt. The sagittal rotation of the anterior pelvic plane is an important measurement of pelvic tilt during hip surgery. Thus, correct evaluation of cup position and acetabular parameters requires the assessment of pelvic tilt in AP radiographs. Changes in pelvic tilt inversely change the height of the lesser pelvis and the obturator foramen in AP radiographs. Tilt ratios were calculated by means of these two parameters in simulated radiographs for ten male and ten female pelvises in defined tilt positions. A tilt formula obtained by exponential regression analysis was evaluated by two blinded investigators by means of 14 simulated AP radiographs of the pelvis with pelvic tilts ranging from + 15° to -15°. No differences were found between male and female tilt ratios for each 5° step of simulated pelvic tilt. Pelvic tilt and tilt ratios correlated exponentially. Using the tilt formula, the two blinded investigators were able to assess pelvic tilt with high conformity, a mean relative error of + 0.4° (SD ± 4.6°), and a mean absolute error of 3.9° (SD ± 2.3°). Neutral pelvic tilt is indicated by a tilt ratio of 0.5 when the height of the lesser pelvis is twice the height of the obturator foramen. The analysis and interpretation of cup position and acetabular parameters may be improved by our method for assessing pelvic tilt in AP radiographs.

Assessment of the orbit morphometry on West Anatolian dry skulls.

The orbit is very frequently damaged by traumas which result in not only bone deficits, but also functional deformities if reconstruction is not appropriate. Anatomical exposure of the bony orbit is of importance for both anatomists and surgeons who perform operation on this area. The current study evaluated the group of morphometrical parameters on 74 adult West Anatolian dry skulls and stereological surface area on the dry skull orbits while describing the clinical importance. Surface areas on the orbital base of the skulls were also evaluated using stereological method, bilaterally. Anthropological assessment of orbital base (in terms of width and height) revealed no significant difference between right and left sides. Both width and height of the optic foramen were significantly higher on the right side compared to left. The distances between the margins (medial, lateral, superior, inferior) of the orbital base and the optic foramen were longer on the right side compared to left, except the distances between the lateral margins. There was no significant difference among the subjects between right and left sides with respect to the orbital base in terms of stereological area calculation. The results are significant because there are no recorded anatomical data on West Anatolian skulls at previous researches. (Folia Morphol 2018; 77, 1: 105-109).

Anatomic analysis of the equine mental foramen and rostral mandibular canal using computed tomography

ObjectivesTo characterize the anatomy of the mental foramen and determine associations with age, weight, sex and breed. Study designRetrospective descriptive study. AnimalsForty-one horses, 0.6–25.2 years and weighing 136–820 kg. MethodsComputed tomography (CT) studies of equine heads performed over 5 years were evaluated in multiplanar and three-dimensional reconstruction. Measurements obtained were positioning of the foramen along the mandible, foramen height and width, foramen–canal angulation and rostral canal mineralization. Exploratory statistical analyses investigated associations between measurements and age, weight, sex and breed. ResultsEvaluation of 41 CT studies revealed foramen positioning was one-third of the horizontal distance of the incisor–premolar space from the second premolar and one-third of the vertical distance in the mandible from the dorsal surface of interproximal space at the level of the foramen. Age was negatively correlated to horizontal positioning [r = –0.42; 95% confidence intervals (CI), –0.64 to –0.13]. Mean foramen width was 6.4 (range, 2.3–17.1) mm and height 5.6 (range, 2.1–10.3) mm. Age and foramen height (r = 0.32; 95% CI, 0.01 to 0.57) and width (r = 0.30; 95% CI, –0.01 to 0.30) were positively correlated. Thoroughbred and Warmblood/Draft horses had increased foramina heights compared with Quarter horses [analysis of variance (anova)p = 0.02]. Males had wider foramina (95% CI, –2.66 to 0.07). Angulation of the foramen–canal was mean ± standard deviation 68.3 ± 12.8° (range, 37.9–105.6°) transverse plane, 28.3 ± 4.1° (range, 18.2–39.0°) saggital plane and 41.4 ± 8.45° (range, 22.2–58.6°) dorsal plane. Older horses had decreased mineralization of the rostral canal (anova, left p = 0.015, right p = 0.025). ConclusionsThe size, shape, positioning and angulation of the mental foramen varies. Mineralization of the canal is decreased in older horses. Clinical relevanceThis study improves understanding of mental foramen anatomy and complications with needle placement.

Skull morphometry and vault sutures of Myrmecophaga tridactyla and Tamandua tetradactyla

ABSTRACT This study aimed to examine the relationship between skull size and the level of cranial vault suture closure. A total of 50 Myrmecophaga tridactyla Linnaeus, 1758 and 178 Tamandua tetradactyla Linnaeus, 1758 skulls were analyzed in relation to 18 skull dimensions. The skulls were grouped into three levels of suture closure: no sutures closed (level 0), one or all the fallowing sutures closed: interfrontalis, sagitalis and coronalis (level 1) and all sutures closed (level 2). The results indicated that among the 18 variables measured, 17 showed significant differences (p ≤ 0.01) between level 0 and level 1 skulls of T. tetradactyla; as well as between level 0 and level 1, and level 0 and level 2 skulls of M. tridactyla. M. tridactyla level 1 and level 2 had no significant difference among any of the 18 dimensions. The foramen magnum height in both species showed no significant difference (p &gt; 0.05) among any suture categories. In principle, suture closure level and cranial dimensions are related. The specimens with larger cranial dimensions showed greater number of cranial vault sutures closed for both species of anteaters. Tamandua tetradactyla and M. tridactyla specimens with none of the cranial vault suture closed have a foramen magnum height similar to those with cranial vault suture closed.

Short-term clinical outcome and radiographic assessment of indirectly decompression of oblique lateral interbody fusion for degenerative lumbar spinal stenosis

Objective To investigate the short-term clinical outcome and radiographic assessment of Oblique Lateral Interbody Fusion to indirectly decompress for the degenerative lumbar spinal stenosis with or without lumbar spine instability. Methods All of 15 patients with diagnosis of degenerative lumbar spinal stenosis with or without lumbar spine instability (7 males and 8 females, age from 36y to 86, mean age 53.5±15.2 y) were treated with OLIF surgery in our spine surgery center. The main symptoms included lumbar pain with unilateral or bilateral leg pain or intermittent claudication. The Visual analogue scale (VAS), Oswestry disability index (ODI), Japanese Orthopaedic Association (JOA) and SF-36 scores were used to assess the clinical effect pre and post-operatively while radiographic assessments were compared as well as comprehensive evaluation of the radiography, MRI, and CT images. Results All patients were followed up for an average of 12.5 (6-21) months. And all the patients enjoyed alleviation of symptoms although varying in extent. The radiographic results showed satisfactory indirect decompression of the neuro-elements, as well as reduction of the lumbar spine. The DH, VH and FH increased by 3.6mm, 4.8mm and 5.7mm respectively. The foraminal area (FA) and canal area (CA) enlarged by 44.2mm2 and 24.8mm2. The canal diameters (CD) and disk-flavum ligamentum space (DLFS) increased by 2.5mm and 2mm respectively. The foraminal diameters (FD) increased by 0.3mm, but there was not significantly different. The segment angle and lumbar lordosis angle were partially restored after operation, and the angle increased by 14 ° and 13.6 °respectively. One of the patients had a transient paresthesia and mild weakness of muscle when hip flexor and recovered within 3 months. Another one case encountered serious back pain after a month and alleviated after reoperation with PPF. Conclusion OLIF can provide a satisfactory outcome for the patients with degenerative lumbar spinal stenosis through indirectly decompression, which can increase the disc height, foramen height, canal diameter and disk-flavum ligamentum space. Key words: Lumbar vertebrae; Spinal stenosis; Spinal fusion

Bony Lateral Recess Stenosis and Other Radiographic Predictors of Failed Indirect Decompression via Extreme Lateral Interbody Fusion: Multi-Institutional Analysis of 101 Consecutive Spinal Levels.

Although extreme lateral interbody fusion (XLIF) largely provides successful indirect decompression, some patients have recurrent same-level pain and functional disability. Identifying risk factors for this failure would facilitate better patient selection and improve outcomes. The aim of this study is to identify preoperative radiographic risk factors for failure of XLIF. Patients undergoing XLIF were prospectively enrolled by 3 surgeons at 3 separate institutions. Radiographic variables measured included (1) anterior and posterior disc height, (2) foramen height and area, (3) central canal diameter, (4) central canal area, (5) right and left subarticular diameters, (6) facet arthropathy grade, and (7) presence of bony lateral recess stenosis. Patients failed indirect decompression if Oswestry Disability Index (ODI) scores did not improve by 20 points or revision surgery was required within 6 months postoperatively. Univariate and multivariate analyses were performed to identify radiographic predictors of failure of indirect decompression. Of the 45 patients (age 65.6 ± 10.5 years; 14 male) involving 101 spinal levels included in this study, 13 (29%) failed indirect decompression. From univariate analysis, these patients had significantly smaller central canal diameter, foraminal height, and disc height (P < 0.05). In multivariate analysis of these parameters and those trending toward significance, bony lateral recess stenosis was the only significant independent predictor for failure of indirect decompression (coefficient, 0.55 [0.24-0.85]; P < 0.001). Bony lateral recess stenosis is an independent predictor for failure to achieve adequate spinal decompression via XLIF and thus may benefit from undergoing direct decompression.

Anatomic basis of Le Fort 1 impaction osteotomy: a radiological study.

In Le Fort 1 osteotomy when a maxillary impaction is necessary, surgeons have to face different anatomical problems. (1) To determine the best bone resection route, they have to consider the situation of dental roots, infraorbital foramen and maxillary artery. (2) In case of Le Fort 1 osteotomy combined with a mandibular sagittal split osteotomy, the palate has to be replaced in horizontal position although there is no anatomical landmark. (3) In case of Gummy smiles, it can be due to either long face or short upper lip. The main objective was to identify safe bony landmarks to perform a Le Fort I osteotomy and to find a reliable way for repositioning the palate horizontally; the secondary objective was to determine the upper lip normal length. The study was based on 178 facial CT examinations. The following parameters have been used: the vertical length of the upper lip, the vertical heights of the anterior nasal spine, the canine and molar roots, the inferior limit of the pterygomaxillary fossa and the vertical height of the infraorbital foramen on both sides. The vertical length from the subnasal point to the upper vermilion was 15.06±3.09mm, and to the junction of the upper and lower lips was 23.94±3.79mm. The vertical length from the anterior nasal spine to the incisor alveolar border was 19.70±3.17mm. The height of the canine root was 17.11±2.60mm. The height of the highest lateral root of first or second maxillary molars was 11.71±1.83mm. The vertical length from the inferior limit of the pterygomaxillary fossa (pti point) to the alveolar border of the pterygomaxillary suture was 19.86±3.45mm. The height from the center of the infraorbital foramen to the alveolar border of the maxilla on a vertical line was not statistically different on right and left sides. According to our results, in impaction Le Fort 1 osteotomy, the bone resection must pass 20mm above the alveolar border in canine area, and 15mm above the alveolar border in molar area. The resection has to end less than 20mm above the inferior border of the pterygomaxillary suture. The vertical height of the infraorbital foramen is a consistent landmark for repositioning of the palate in a horizontal plane.

Percutaneous transforaminal endoscopic discectomy combined with Coflex interspinous process dynamic reconstruction system in treatment of youth lumbar disc herniation

To evaluate the effectiveness of percutaneous transforaminal endoscopic discectomy (PTED) combined with Coflex interspinous process dynamic reconstruction system for the treatment of youth lumbar disc herniation (LDH). The clinical data of 52 patients with LDH treated by PTED combined with Coflex were retrospectively analyzed between February 2013 and March 2015. The involved segments were L 4, 5 in 30 cases and L 5, S 1 in 22 cases. In 30 patients at L 4, 5 level, there were 18 males and 12 females with an average age of 25 years (range, 18-34 years) and a mean disease duration of 10 months (range, 6-16 months). In 22 patients at L 5, S 1 level, there were 10 males and 12 females with an average age of 25.5 years (range, 19-32 years) and a mean disease duration of 12 months (range, 6-18 months). The operation time and intraoperative blood loss were recorded. Oswestry disability index (ODI) and Japanese Orthpoaedic Association (JOA) score were used for effectiveness assessment. Radiograpic indexes were calculated on X-ray films before operation and final follow-up, including ventral intervertebral space height (VH), dorsal intervertebral space height (DH), intervertebral foramen height (IFH), the range of motion (ROM) of involved segment, and the ROM of upper adjacent segment. The operations were successfully completed in 52 patients. The operation time and intraoperative blood loss were (89.7±16.5) minutes and (42.7±11.3) mL in patients at L 4, 5 level, and were (94.6±18.2) minutes and (47.6±13.4) mL in patients at L 5, S 1 level. Incisions healed by first intention. All patients were followed up 12-18 months (mean,16 months) in patients at L 4, 5 level and 12-20 months (mean, 17 months) in patients at L 5, S 1 level. At final follow-up, ODI, and JOA score were significantly improved when compared with preoperative ones in all patients ( P<0.05). X-ray films showed no complication of Coflex loosening, spinous process fracture, or articular process fracture occurred. At final follow-up, VH, DH, and IFH were significantly improved when compared with preoperative ones in all patients ( P<0.05), and the ROM of involved segment was significantly reduced compared with preoperative one ( P<0.05), but the ROM of upper adjacent segment showed no significant difference when compared with preoperative one ( P>0.05). PTED combined with Coflex is a safe and effective minimally invasive surgery in treating youth LDH; however, it still needs further clinical studies.

Spatial evaluation of Mental Foramen among UAE locals attending UDHS using CBCT

Aim: Mental foramen could be an area subjected to trauma due to surgery or implant placement in mental area. Our aim is to measure the different parameters of the mental foramina of males and females among UAE Nationals visiting the University Dental Hospital Sharjah to enhance our knowledge of the possible locations of the mental foramen in order to prevent iatrogenic injuries through periodontal and endodontic surgeries, local anesthesia and implant placement. Materials and Methods: This study was a retrospective study and samples included in the study were UAE nationals who already underwent a CBCT examination in the University Dental Hospital Sharjah in the period of 2010 till 2015. All samples were for nationals of the United Arab Emirates between the age of 18 and 65 whose CBCT scans shows the mental foramen area and the adjacent teeth (lower canines and first molars). Parameters measured in the mental foramen included height of foramen, width of foramen, shortest distance from foramen to adjacent tooth. Results: There was a statistically significant gender difference between the mean value of mental foramen height(3.77 mm±0.86 mm for males) and 3.10 mm ± 0.8mm for females) (P = 0.002).The shortest distance of the foramen to the adjacent tooth also showed statistically significant gender differences(4.68mm ± 3.23mm for males) and (4.71 mm±1.94 mm for females), f (p= 0.012). Conclusion: The height of the foramen and the distance of MF to the most adjacent tooth were greater in UAE males than in females. Discrepancy in the height of the foramen when dealing with different ethnicities should betaken into consideration. Clinical Significance: MF is an important anatomical landmark for dental surgeons performing periapical surgery in the mental region such as endodontic and periodontal procedures. In order to avoid any nerve damage during oral surgery, MF location should be identified while keeping in mind the possibility of an anterior loop of the mental nerve being present mesial to the mental foramen. This should also be noted whilst performing surgery for implant placement.