Pedicle Width Research Articles

A comparative shape analysis of the cervical spine between individuals with cervicogenic headaches and asymptomatic controls

As some researchers theorized that cervicogenic headache (CEH) might be related to bony and discal features of the cervical spine, this retrospective study examined the shapes of the cervical vertebrae and intervertebral discs (IVDs) of individuals with CEH and compared them to asymptomatic controls. Scans of 40 subjects in their late 20’s–mid 30’s affected with CEH and 40 asymptomatic controls were obtained (overall = 19,040 measurements, age-sex matched, 20 males and 20 females in each group). The following cervical spine variables were measured: Supine lordosis, vertebral body-heights, A-P lengths, mediolateral widths and sagittal-wedging; IVDs heights and sagittal-wedging; pedicle heights, widths and transverse angles; laminar widths and transverse angles; articular facet angles, spinal canal, and transverse foramen lengths, widths, and areas. Both groups had similar shape variation along the cervical in all the measured parameters. There were no significant left–right differences in all measured parameters and no significant differences between the CEH and control groups concerning sex and age. Cervical IVDs were lordotic in shape, whereas their adjacent vertebral bodies were kyphotic in shape except for C2. In conclusion, the shape of the cervical spine and IVDs in subjects in their late 20’s–mid 30’s affected with CEH is identical to asymptomatic controls.

Determination of Availability of Safety Margin for Placement of C3-C6 Pedicle Screw on CT Angiography

Cervical pedicle screws (CPS) in the subaxial cervical spine (C3-C6) are faced with high incidence of perforating the lateral pedicular cortex endangering the vertebral artery (VA). The present study analyzes the pedicle width (PW) from C3 to C6 and defines the relation of VA with regard to pedicle and transverse foramen (TF) to determine the safety margin in cases of lateral pedicular breach. Computed tomography angiograms of 500 patients were retrospectively studied to identify the pedicle width (PW), VA area, TF area, and the lateral pedicle to vertebral artery distance (LPVA). Occupancy ratio (OR; the percentage area of transverse foramen occupied by VA) and safety margin (SM; permissible displacement of VA in TF), along with LPVA were considered to be protective parameters against VA injury if lateral pedicle breach happens. PW was 4.7 mm at C3, 4.83 mm at C4, 5.26 mm at C5 and 5.41 mm at C6. Mean LPVA at different levels was between 0.97 mm and 1.15 mm, OR was around 20% at all levels, and mean SM was between 2.34 mm and 2.92 at various levels. Sex differences were statistically significant for PW but not for LPVA, SM, or OR. This study gives us an idea about the various parameters in placement of cervical pedicle screw in subaxial cervical spine and the probable reasons there are few vertebral artery injuries despite high incidence of cervical pedicle breach. LPVA, safety margin, and OR may explain why even very significant CPS misplacement does not lead to vascular injury or neurologic deficit.

The association between atlantoaxial instability and anomalies of vertebral artery and axis

BACKGROUND CONTEXTA screw-rod system is the most widely used technique for atlantoaxial instability (AAI). However, neglecting anomalies of the vertebral artery and axis could lead to fatal complications. Whether or not the presence of AAI is associated with a more complicated anatomy for instrumentation is unclear. PURPOSETo analyze the association between AAI and anomalies of the vertebral artery and axis in patients with and without AAI. STUDY DESIGNA retrospective comparative study. PATIENT SAMPLEOne hundred and twenty patients who underwent preoperative 3-dimensional computed tomography with vertebral angiography of the cervical spine at our institution from 2012 to 2020. OUTCOME MEASURESThe C2 isthmus height, internal height of the C2 lateral mass, and C2 pedicle width were radiologically assessed. METHODSA case control study with matched cohort analysis was conducted. One hundred and twenty patients were divided into 2 groups according to presence of AAI, and the presence of high-riding vertebral artery (HRVA) and a narrow pedicle for insertion of the C2 pedicle screw was assessed, as was the prevalence of extraosseous vertebral artery anomaly. RESULTSThe C2 isthmus height, C2 internal height, and C2 pedicle width were significantly narrower in the AAI group (p<.01, <.01, and <.01, respectively). A significantly greater proportion of patients with AAI had HRVA and a narrow pedicle than those without (p<.01 and < 0.01, respectively). Among patients with AAI, the C2 internal height was significantly narrower in patients with rheumatoid arthritis (p<.01). Five patients (8.3%) with AAI had vertebral artery anomaly (3 fenestration, 2 persistent first intersegmental artery), while there were no vertebral artery anomalies in patients without AAI (p<.01). CONCLUSIONSVertebral artery anomalies are more common in patients with AAI. Furthermore, posterior instrumentation in patients with AAI has a narrower safe zone compared to that in patients without AAI, which may be caused by a long-lasting deformity rather than a congenital deformity. Therefore, more thorough preoperative evaluation of the anatomy should be performed in these patients.

Predictors of the surgical outcome of propeller perforator flap reconstruction, focusing on the effective safe distance between the perforator and the wound edge

BackgroundSoft tissue defects in the distal third of the leg and malleolus are difficult to cover and often require free tissue transfer, even for small-sized defects. Propeller flaps were designed as an alternative to free tissue transfer, but are reportedly associated with high complication rates. The aim of our study was to assess our institutional experience with the propeller flap technique and to predict its outcome in lower-limb reconstruction.MethodsAll patients who had undergone propeller flap reconstruction of a distal leg defect between 2013 and 2018 were included. Demographic, clinical, and follow-up data were analyzed.ResultsComplications occurred in 17 of 82 propeller flaps (20.7%), comprising 11 cases of partial necrosis and six of total necrosis. There were no significant differences in age, sex, body mass index smoking, diabetes mellitus, and soft tissue defect sites between the groups of patients with versus without flap necrosis (p > 0.05). In univariate analysis, there were also no significant differences between these two groups in the length and width of the fascial pedicle, and the ratio of the flap length to the flap width (p > 0.05). Interestingly, there were significant differences between the two groups in the distance between the flap perforator, the shortest distance from the perforator to the defect location, and the rotation angle of the flap (p < 0.05). In multivariable logistic regression analysis with odds ratios (ORs) and 95% confidence intervals (95% CIs), the shortest distance from the perforator to the defect location was a significant risk factor for flap complications (p = 0.000; OR = 0.806). Receiver operating characteristic curve analysis showed that when the shortest distance from the flap to the wound was less than 3.5 cm, the necrosis rate of the flap was markedly increased (AUC = 76.1); this suggests that the effective safe flap–wound distance was 3.5 cm.ConclusionsPropeller flaps are a reliable option for reconstruction in carefully selected patients with traumatic defects of the lower limb and malleolus. We found that the effective safe distance was 3.5 cm from the flap to the wound.

A Single-Center Surgical Experience With the Reverse Sural Artery Flap as a Reliable Solution for Lower Leg Soft Tissue Defects, With Minimum Two-Year Follow-Up.

Aim: Small soft tissue defects of the distal tibia and hindfoot resulting from traumatic, operative, or neoplastic conditions and chronic ulcers can be successfully dealt with the use of the reverse sural artery flap (RSAF). This study aims to describe a single center’s results and familiarity with this technique over a 15-year period of time.Material and methods: We retrospectively reviewed the clinical files of patients who were consecutively treated with RSAF and regularly followed up between January 1, 2004 and December 31, 2018, with a minimum postoperative follow-up period of two years. Patient demographics and comorbidities, location of the defect, performing surgeon, mean operation time, flap pedicle width, mean size of the defect, days of hospitalization following the operation, healing flap rate, and complications were recorded.Results: The sample consisted of 30 adult patients (25 men, 5 women), with a mean age of 51.07 years (16-80 years, SD 18.61). The mean operation time was 99.03 min (range 83-131, SD 10.57), and the mean size of the defect was 11.11 cm2 (range 6.1-19.4, SD 3.22). Successful flap rate (complete healing and coverage of the defect, with or without additional minor intervention) was 83.3% (25/30). Among successfully healed flaps, six patients with partial necrosis of the dermis were treated by an additional split-thickness skin graft. Five flaps failed to heal. Deep infection was present in two patients, leading to flap failure and reoperation. Serious venous congestion resulting in flap ischemia occurred in three cases. Circumferential keloid formation (not affecting successful outcome) was present in seven cases. Flap thickness approximated to normal within six months. All donor sites healed well (either by a split-thickness cutaneous flap or by immediate wound closure). Light paresthesia on the lateral border of the leg and foot disappeared within six months.Conclusions: A single-center experience with the RSAF has yielded satisfactory clinical outcomes, and the long-term tackle with the difficult reconstruction conditions around the ankle, has led to valuable advice on surgical technique and postoperative protocol, based on an anatomical basis.

Spinal Pedicle Morphometry using Multidetector CT—An experience from the Indian Subcontinent

Abstract Introduction For safe pedicle screws placement, knowledge of pedicle morphometry is essential, because an inconsistency between pedicle width and the screw diameter may lead to severe complications like nerve, vessel or visceral injuries. Objectives To study the spinal pedicle width and height of lumbar spine, using multidetector CT (MDCT), among the Indian population. To study the spinal pedicle angulation of lumbar spine, using MDCT, among the Indian population. Method The study was conducted at a tertiary care multispecialty hospital. In the present study, a total of 321 patients were included, who underwent MDCT scan without contrast at our institution, over a period of 2 years, from May 2017 to May 2019. The study population (n = 321) was divided into different subgroups on the basis of the age. The data was taken from the workstation. Comparison was made separately between each subgroup. Results In our subset of population, the 10 to 90 years age group, pedicle dimensions are as follow: The pedicle diameter from L1 to L5 is 4.46 to 11.92 mm. The pedicle height from L1 to L5 is 7.38 to 11.01 mm. The pedicle axial angulation from L1 to L5 is 22.27 to 36.08 degree. The pedicle lateral angulation from L1 to L5 is 16.12 to 22.47 degree. Conclusion Knowledge of the pedicle morphometry (pedicle width, height and angulation) of lumbar spine will help the neurosurgeons standardize the size of pedicle screws which is required for spinal fixation surgery at various lumbar vertebra levels.

Clinical study of modified technique to reduce partial necrosis rate of distally pedicled sural flap

To investigate whether the technical modifications regarding the risk factors related to the partial necrosis of the distally pedicled sural flap could reduce the partial necrosis rate of the flap. A clinical data of 254 patients (256 sites) (modified group), who used modified technique to design and cut distally pedicled sural flaps to repair the distal soft tissue defects of the lower limbs between April 2010 and December 2019, was retrospectively analyzed. Between April 2001 and March 2010, 175 patients (179 sites) (control group) who used the traditional method to design and cut the skin flap to repair the distal soft tissue defects of the lower limbs were compared. Various technical modifications were used to lower the top-edge of the flap, reduce the length-width ratio (LWR) of the flap and width of the skin island. There was no significant difference in gender, age, etiology, duration from injury to operation, site and area of the soft tissue defect between groups ( P>0.05). The length and width of the skin island and adipofascial pedicle, the total length of the flap and LWR, and the pivot point position were measured and recorded. The top-edge of the flap was determined according to the division of 9 zones in the posterior aspect of the lower limb. The occurrence of partial necrosis of the flap and the success rate of defect reconstruction were observed postoperatively. There was no significant difference in the length and width of the skin island, the length of the adipofascial pedicle, total length and LWR of the flap, and pivot point position of the flap between groups ( P>0.05). The width of the adipofasical pedicle in modified group was significant higher than that in control group ( t=-2.019, P=0.044). The top-edge of 32 flaps (17.88%) in control group and 31 flaps (12.11%) in modified group were located at the 9th zone; the constituent ratio of the LWR more than 5∶1 in modified group (42.58%, 109/256) was higher than that in control group (42.46%, 76/179); and the constituent ratio of width of skin island more than 8 cm in control group (59.78%, 107/179) was higher than that in modified group (57.42%, 147/256). There was no significant difference in the above indicators between groups ( P>0.05). In control group, 155 flaps (86.59%) survived completely, 24 flaps (13.41%) exhibited partial necrosis. Among them, 21 wounds healed after symptomatic treatments, 3 cases were amputated. The success rate of defects reconstruction was 98.32% (176/179). In modified group, 241 flaps (94.14%) survived completely, 15 flaps (5.86%) exhibited partial necrosis. Among them, 14 wounds healed after symptomatic treatments, 1 case was amputated. The success rate of defect reconstruction was 99.61% (255/256). The partial necrosis rate in modified group was significantly lower than that in control group ( χ 2=7.354, P=0.007). There was no significant difference in the success rate between the two groups ( P=0.310). All patients in both groups were followed up 1 to 131 months (median, 9.5 months). All wounds in the donor and recipient sites healed well. The partial necrosis rate of the distally based sural flap can be decreased effectively by applying personalized modified technical for specific patients.

Computerized Tomographic Based Study of Thoracic Spine Morphology in Relevance to Pedicle Screw Fixation in Pakistani Population

Objective: To study the thoracic spine anatomy for accurate placement of pedicle screws using computerized tomography.&#x0D; Material and Methods: CT scans of 200 patients were included in our study. T1 to T12 vertebrae morphology was studied for each patient. Following measurements were taken, 1: Transverse pedicle width, 2 = Depth of anterior cortex along pedicle axis, 3 = Transverse pedicle angle, 4 = canal dimensions, 5 = vertebral body height anterior and posterior, 6 = mid vertebral body width.&#x0D; Results: Transverse pedicle width decreased from T1 (4.06 ± 0.50 mm) to T4 (3.72 ± 0.17 mm) and then gradually increases to T12 (6.08 ± 0.60 mm). Depth of the anterior vertebral cortex remained constant from T1 to T4 and gradually increases up to T12. Transverse pedicle angle remained constant from T1 to T4 with a maximum at T4 (23.39 ± 3.15 mm) and then gradually decreased to T12 (3.99 ± 2.16 mm). Anteroposterior (AP) canal dimensions were minimum at T7 (17.03 ± 1.01 mm) and maximum at T2 (21.2 ± 1.07 mm). Interpedicular (IPD) canal dimensions were minimum at T6 (19.18 ± 1.6 mm) and maximum at T3 (23.18 ± 1.2 mm). Anterior vertebral body height was minimum at T1 (16.9 ± 1.34 mm) and maximum at T12 (27.14 ± 1.34mm). Posterior vertebral body height was minimum at T1 (18.8 ± 1.13 mm) and maximum at T12 (29.76 ± 1.43 mm).&#x0D; Conclusion: A detailed anatomy of the thoracic spine is essential for surgical planning to decrease postoperative complications.

What is the difference in pedicle morphology of the fifth lumbar vertebra between isthmic and degenerative L5-S1 spondylolisthesis? An anatomic study of 328 patients via multi-slice spiral computed tomography.

The purpose of this study was to investigate and determine whether there are differences in L5 pedicles morphology between isthmic and degenerative L5-S1 spondylolisthesis. One hundred and nineteen patients with isthmic spondylolisthesis and 45 patients with degenerative spondylolisthesis at L5-S1 were enrolled in the IS group and DS group, respectively, and 164 lumbar disc herniation patients without spondylolysis or spondylolisthesis were classified into the normal (NL) group. A series of pedicle parameters of the fifth lumbar vertebra, including pedicle length (PL), pedicle width (PW), pedicle screw trajectory length (PSTL), pedicle height (PH), and the pedicle camber angle (PCA), were measured using multi-slice spiral computed tomography (MSCT). The slip distance of the L5 vertebra was measured on radiography, and the percentage of slip was also recorded. The pedicles of the fifth lumbar vertebra were shorter and wider, and the PCA was larger in the IS group compared to the DS group and NL group. On the contrary, the pedicles in the DS group were elongated and thinner, and the PCA was smaller. The pedicle parameters of PL were significantly positively correlated with the percentage of slip in the DS group, but PW and PCA were negatively correlated with the percentage of slip. There was no correlation between the percentage of slip and L5 pedicle parameters in the IS group. The L5 pedicles morphology in L5-S1 isthmic spondylolisthesis shows abduction, shortness, and width, while that in the degenerative spondylolisthesis shows adduction, lengthening, and thinning compared with the normal populations. The morphology changes may be the result of pedicle stress remodelling in the development of spondylolisthesis, which should be taken into consideration when placing at the insertion of pedicle screws.

Effectiveness of the Reverse Sural Flap in Covering Diabetic Foot Ulcers: A Systematic Review and Meta-Analysis.

Background: The reverse sural fasciocutaneous flap (RSFCF) has been used with success to cover noncomplicated foot and ankle soft tissue defects. However, there are some controversies when it is used in patients having chronic diabetic foot ulcers. This aim of this meta-analysis was to evaluate the efficacy of RSFCF in covering diabetic foot and ankle ulcers. Methods: A systematic review was undertaken from MEDLINE, EMBASE, Web of Science, Cochrane Library, and Google Scholar. Only diabetic foot and ankle ulcers were accepted for inclusion and all study designs were included. Proximally based flaps, nondiabetic ulcers, and assisted negative pressure therapy were excluded. Suitability for inclusion was assessed by 2 reviewers. The random-effect estimate was reported for the set outcomes whenever high heterogeneity was present. Metaregression analysis was performed to identify independent risk factors for failure. Results: The search identified 33 relevant studies comprising 187 patients and flap interventions; all but 1 were case-series. The weighted outcomes were as follows: (1) the flap healing rate was 93.3% while 6.6% resulted in total necrosis, (2) the rate of partial flap necrosis was 12%, (3) venous congestion was reported in 6.6% of cases, (4) the infection rate was 8.3%, and (5) the donor site morbidity was 4.6%. No association was found between pedicle width or presence of a subcutaneous pedicle tunnel and the primary outcome of total loss. Conclusions: This review demonstrated excellent results of the flap when covering complicated or large diabetic foot and ankle ulcers. When compared to those published in the literature, our results found RSFCF to be relatively less successful in diabetic wounds than in trauma patients but more successful than in those having associated osteomyelitis and those who were treated with random local flaps.

Morphometric Analysis of Subaxial Cervical Spine Pedicles in a Middle Eastern Population.

Pedicle screw instrumentation of the posterior cervical spine is the most secure form of fixation available to surgeons. It has not achieved widespread use yet in the Middle East, mostly due to concerns regarding its feasibility in the target population. A detailed morphometric analysis of the lower cervical spine pedicles using computerized tomography (CT) was proposed to address this issue. Two hundred and seventy patients were enrolled in the study. CT scans were reviewed by two experienced assessors, and measurements of pedicle width (PW), height (PH), and transverse angle (TA) were recorded for all patients. Interobserver and intraobserver reliability were calculated using the kappa statistic. Sex differences were also recorded and analyzed. The t test was used to assess for any significant differences in measurements due to sex (P < .05). The mean PW varied from 4.4 mm in C3 to 6.1 mm in C7. The mean PH was 6.4 mm in C3 and 6.8 mm in C7. Pedicle TA varied from 42 to 51 degrees between the different levels. Sex differences were observed and were statistically significant for PW and PH. Interobserver reliability was high for PW and PH, but was low for TA. Intraobserver reliability was 0.99 for both assessors. This study provides reliable PW and PH measurements and demonstrates that cervical pedicle screw instrumentation is feasible in our local population. Significant variability exists, however, and each patient must be addressed individually for best results. 3. This study shows that the morphology of the subaxial cervical pedicle permits instrumentation in a majority of cases of our target population.

Assessment of pedicle size in patients with scoliosis using EOS 2D imaging: a validity and reliability study

PurposeFree-hand pedicle screw insertion methods are widely used for screw insertion during scoliosis surgery. Preoperative knowledge about the pedicle size helps to maximize screw containment and minimize the risk of pedicle breach. Radiographs taken by a biplanar low-dose X-ray device (EOS) have no divergence in the vertical plane. The criterion validity and reliability of preoperative EOS images for pedicle size measurements in patients with idiopathic scoliosis (IS) was investigated in this study.MethodsSixteen patients who underwent surgical treatment for IS were prospectively included. Intra- and extracortical pedicle height and width measurements on EOS images were compared with reconstructed intra-operative 3D images of the isthmus of included pedicles. Secondly, intra- and interobserver reliability of pedicle size measurements on EOS images was determined.ResultsThe total number of analyzed pedicles was 203. The correlation between the EOS and 3D scan measurements was very strong for the intra- and extracortical pedicle height and strong for the intra- and extracortical pedicle width. There are, however, significant, but likely clinically irrelevant differences (mean absolute differences < 0.43 mm) between the two measure methods for all four measurements except for extracortical pedicle height. For pedicles classified as Nash–Moe 0, no significant differences in intra- and extracortical pedicle width were observed. Both intra- and interobserver reliability was excellent for all pedicle size measurements on EOS images.ConclusionThe results of this study indicate a good validity and reliability for pedicle size measurements on EOS radiographs. Therefore, EOS radiographs may be used for a preoperative estimation of pedicle size and subsequent screw diameter in patients with IS.

Computed tomographic analysis of cervical spine pedicles in the adult Indian population.

Background: Cervical pedicle screw insertion is a technically demanding procedure that carries the risk of catastrophic damage to surrounding neurovascular structures. Here, we analyzed computed tomography (CT)-based three-dimensional cervical spine pedicle geometry to determine the level and sex-specific morphologic differences in the adult Indian population.Methods: The CT scans of 200 patients (2400 pedicles) without significant cervical spine pathology were collected. The mean pedicle width (PW), pedicle height (PH), pedicle axial length (PAL), and pedicle transverse angle (PTA) from C2 to C7 were measured.Results: The smallest mean PW was at C3 in both males (4.85 ± 0.73 mm) and females (4.31 ± 0.43 mm); 7.08% of all pedicles were found to have mean PW of <4 mm. The smallest mean PH was at C5 in both males (6.25 ± 0.67mm) and females (5.54 ± 0.52 mm). The smallest mean PAL was at C2 in both males (27.46 ± 1.69mm) and females (25.90 ± 1.88 mm). The mean PW, PH, and PAL were significantly greater in males than females at all levels (P < 0.05). The smallest mean PTA was at C3 in males (41.79 ± 2.53°) and at C7 in females (42.40 ± 2.27°).Conclusion: In the adult Indian population, the PW, PH and PAL were smaller than in the typical western population. Females had even smaller PW, PH and PAL as compared to males. We recommend that a small inventory of 3.5mm screws between 20mm to 30mm length be used in most cases where cervical pedicle screws are being used in the Indian population. However, individual vertebrae should be screened preoperatively with CT scans to exclude gross anatomical variations, especially in females and at the C3 and C4 levels.

Risk factors related to the partial necrosis of the posterior tibial artery perforator-plus fasciocutaneous flap.

The posterior tibial artery perforator-plus fasciocutaneous (PTAPF) flap is commonly used for defects over the distal lower extremity. However, the causes of partial necrosis of the PTAPF flap are unknown. This paper aimed to explore the factors related to the partial necrosis of the PTAPF flap. A retrospective study was conducted on 59 patients who received the PTAPF flap for soft-tissue defects between September 2007 and September 2017. The clinical outcomes of the flap were evaluated, and the patient and surgical factors related to flap survival were analyzed. Of the 59 patients, 9 (15.25%) flaps exhibited partial necrosis. No significant differences were found between the survival and partial necrosis groups regarding gender, age, soft tissue defect site, length and width of the fascia pedicle, length of the skin island, length-width ratio (LWR), and pivot point (P > 0.05). However, the survival group showed significantly less width of the skin island and total length of the flap than the partial necrosis group (P < 0.05). Multiple logistic regression analysis revealed that the width of the skin island was an independent risk factor affecting partial flap necrosis (OR = 4.028; P = 0.041). The PTAPF flap can be effectively used to repair small and medium wounds of the lower and middle leg, ankle and foot. As the width of the skin island exceeds 6cm, the risk of partial flap necrosis significantly increases.

Lumbar Pedicle Morphology and Vertebral Dimensions in Isthmic and Degenerative Spondylolisthesis-A Comparative Study.

The pedicle screw is the most common device used to achieve fixation in fusion of spondylolistheses. Safe and accurate placement with this technique relies on a thorough understanding of the bony anatomy. There is a paucity of literature comparing the surgically relevant osseous anatomy in patients with a degenerative spondylolisthesis (DS) and an isthmic spondylolisthesis (IS). The goal of this study was to determine the differences in the osseous anatomy in patients with a DS and those with an IS. A retrospective comparative cohort study was conducted on patients with a single-level, symptomatic L4-L5 DS or a single-level, symptomatic L5-S1 IS. Magnetic resonance imaging for these patients was reviewed. Morphometries of the pedicle and vertebral body were analyzed by 2 independent observers for the levels from L3 to S1, and radiographic parameters were compared between groups. A total of 572 levels in 143 patients were studied, including 103 patients with a DS and 40 with an IS. After accounting for confounders, IS and DS had an independent effect on transverse vertebral body width, pedicle height and width, and sagittal pedicle angle. Patients with an IS had a smaller pedicle height (P < .001) and pedicle width (P = .001) than patients with DS. In addition, the angulation of the pedicles varied on the basis of the diagnosis. The osseous anatomy is significantly different in patients with a DS than with an IS. Patients with an IS have smaller pedicles in the lumbar spine. Also, the L4 and L5 pedicles are more caudally angulated and the S1 pedicle is less medialized. 3. Understanding the differences in pedicle anatomy is important for the safe placement of pedicle screws.

Thoracic and lumbar spine pedicle morphology in Japanese patients.

Pedicle morphology is important for intraoperative surgical anatomy and to define pedicle screw design and parameters. However, differences of pedicle size according to ethnicity and gender are not well studied. The purpose of this study is to investigate morphological characteristics of the pedicle in Japanese patients for determining adequate screw size and optimal surgical planning. We investigated thoracic and lumbar pedicle morphology in Japanese patients using computed tomography (CT) measurements and analyzed the standard size of pedicles on upper thoracic to lumbar spine CT images in 227 Japanese patients. Gender had a larger impact on the shape and size of pedicles than racial differences. In the distribution of pedicle width, we calculated the ratio of values less than 4.5mm, that in females resulted to be over 30% for the Th3-Th9 segment, and particularly high, above 60% at Th4 and Th5. Our measurement analysis showed that pedicle morphological parameters in Japanese patients showed tendency to be smaller to those found in other studies, and particularly in female patients, they were statistically significantly smaller. Adequate transpedicular instrumentation for Japanese patients will require smaller size pedicle-related devices that will match our anatomical findings to achieve safe device placement. In addition, serving ethnically non-homogenous patient population can require further to spinal morphometric for precise device selection.

Fourth lumbar vertebral parameters in predicting the gender, height and age in Iranian population

IntroductionLumbar vertebral dimensions can be considered as a criterion to diagnose unidentified individuals with severe burning or corpses. The aim of this study was to evaluate gender, age, and height using the parameters of fourth lumbar vertebral (L4). MethodsThis cross-sectional study was carried out on 106 volunteers. Lumbar diameters of L4 were measured in the two sagittal and horizontal sections by three-dimensional CT scan with reconstruction and volume rendering. The measured parameters were Upper end plate depts (EPD); Upper end plate widths (EPW); Anterior height of vertebral body (VBH); Foramen diameter (depts.) (FDS); Foramen diameter (widths) (FDC); Pedicle height (PH); Pedicle widths (PW); Articular process height (APH); Maximum distance between (ADM); Transverse process distance (TDM); Spinal process height (SPH); Spinal process lengths (SPL); and Vertebral lengths (VL). These parameters were compared. The relationship of each parameter was evaluated with age, height and gender. ResultsTotally, the mean parameters of L4 was higher in men compared to women, but this difference was not significant in FDS, APHI, and SPL. In the study of the correlation of diameters with age, only EPD and SPL parameters were significant, but in the linear regression model to predict age, only the FDS index showed a significant relationship. All parameters except APHS, APHI, SPL, and VL showed a significant and positive correlation with height. But in the linear regression model to predict height, only a significant relationship was reported for EPD. ConclusionIt was shown that the parameters of the fourth lumbar vertebra can be helpful to determine the age, height, and gender.

Accuracy and technical limits of percutaneous pedicle screw placement in the thoracolumbar spine.

The two-dimensional fluoroscopic method of percutaneous pedicle screw instrumentation has been clinically described as reliable method in the caudal thoracic and lumbosacral spine. Its accuracy has not been clearly reported in the cranial thoracic spine. The aim of this in vitro study was to investigate percutaneous pedicle screw placement accuracy according to pedicle dimensions and vertebral levels. Six fresh-frozen human specimens were instrumented with 216 screws from T1 to S1. Pedicle isthmus widths, heights, transversal pedicles and screws were measured on computed tomography. Pedicle cortex violation ≥ 2mm was defined as screw malposition. The narrowest pedicles were at T3-T5. A large variability between transversal pedicle axes and percutaneous pedicle screw was present, depending on the spinal level. Screw malposition rates were 36.1% in the cranial thoracic spine (T1-T6), 16.7% in the caudal thoracic spine (T7-T12), and 6.9% in the lumbosacral spine (L1-S1). The risk for screw malposition was significantly higher at cranial thoracic levels compared to caudal thoracic (p = 0.006) and lumbosacral (p < 0.0001) levels. Cortex violation ≥ 2mm was constantly present if the pedicle width was < 4.8mm. Percutaneous pedicle screw placement appears safe in the caudal thoracic and lumbosacral spine. The two-dimensional fluoroscopic method has a limited reliability above T7 because of smaller pedicle dimensions, difficulties in visualizing radiographic pedicle landmarks and kyphosis.

Morphometric Study of Atypical Lumbar Vertebrae and their Clinical Significance

Introduction: Lumbar pedicles are short and strong. They form an important part of lumbar spine and play role in transmission of weight from neural arch to the anterior part of vertebral column. Fractures, tumours and degenerative diseases of lumbar vertebrae are common. Pedicle screw fixation is needed to stabilise the vertebrae if required. Only few studies are available for atypical lumbar vertebrae. Aim: To determine the various morphometric measurements of fifth lumbar vertebrae and to discuss the various applied aspects of the study. Materials and Methods: This cross-sectional study was conducted for a period of one year from March 2016 to February 2017. Eighty-five adult human fifth lumbar vertebrae were identified with its atypical features and were examined. Various morphometric measurements- pedicle length, pedicle height and pedicle width, inter pedicle distance, transverse pedicle angle, sagital pedicle angle, chord length, vertebral body height, vertebral body width and vertebral canal measurements were taken using sliding vernier caliper with a least count of 0.1 mm. The data were entered in Microsoft excel and were analysed. Results: A total of 85 fifth lumbar vertebrae were examined. Mean Pedicle Height of L5 vertebrae on both the sides were equal (8.4±3.74). Mean pedicle length of L5 vertebrae and mean transverse pedicular angle of L5 vertebrae were more on the right side than on the left side. Mean pedicle width, mean sagital pedicular angle and chord length of L5 vertebrae were more on the left side than on the right side in this study. All the measurements were compared with previous authors and found to have similar results. Conclusion: Various morphometric measurements of pedicle of fifth lumbar vertebrae were taken in this study. These morphometric knowledge of the pedicles may be helpful for the orthopaedic surgeons and radiologists for proper selection of the pedicle screw and operative repair.

Morphometric Analysis of C2 Pedicle in 247 Patients and Proposal for Trajectory and Size of Pedicle Screw.

Screw diameters are currently available based on the literature available for the Western population. No data are available in such a large number of patients for the Indian population. The aim of this study was to define the average pedicle size available and to determine the angulation for placement of screws for C2 pedicle in the Indian population. We also try to determine the pedicle screw diameter which can be used universally in most Indian patients, considering the pedicle dimensions. Retrospective morphometric analysis of CT scans of 247 patients (152 M, 95 F) was done to calculate the C2 pedicle width (PW), pedicle height (PH), pedicle length (PL), pedicle transverse angle (PTA) and the craniocaudal angulation (CCA) of the C2 pedicle. Mean PW in females was 5.3 mm and in males it was 5.9 mm. This difference was statistically significant. The mean PH in the study population was 8.9 mm, while the mean PL was 29.7 mm. The mean PTA was 40.0 degrees and the CCA was 28.4 degrees. This is a morphometric analysis of the C2 pedicle which provides information for the surgeons to determine the safe site of entry and trajectory for the screw implantation. We conclude that a screw diameter of 2.7 mm can be safely implanted in a vast majority of the patient population.