Gait-simulating fatigue loading analysis and sagittal alignment failure of spinal pelvic reconstruction after total sacrectomy: comparison of 3 techniques

Object Reconstruction after total sacrectomy is a critical component of malignant sacral tumor resection, permitting early mobilization and maintenance of spinal pelvic alignment. However, implant loosening, graft migration, and instrumentation breakage remain major problems. Traditional techniques have used interiliac femoral allograft, but more modern methods have used fibular or cage struts from the ilium to the L-5 endplate or sacral body replacement with transiliac bars anchored to cages to the L-5 endplate. This study compares the biomechanical stability under gait-simulating fatigue loading of the 3 current methods. Methods Total sacrectomy was performed and reconstruction was completed using 3 different constructs in conjunction with posterior spinal screw rod instrumentation from L-3 to pelvis: interiliac femur strut allograft (FSA); L5–iliac cage struts (CSs); and S-1 body replacement expandable cage (EC). Intact lumbar specimens (L3–sacrum) were tested for flexion-extension range of motion (FE-ROM), axial rotation ROM (AX-ROM), and lateral bending ROM (LB-ROM). Each instrumented specimen was compared with its matched intact specimen to generate an ROM ratio. Fatigue testing in compression and flexion was performed using a custom-designed long fusion gait model. Results Compared with intact specimen, the FSA FE-ROM ratio was 1.22 ± 0.60, the CS FE-ROM ratio was significantly lower (0.37 ± 0.12, p < 0.001), and EC was lower still (0.29 ± 0.14, p < 0.001; values are expressed as the mean ± SD). The difference between CS and EC in FE-ROM ratio was not significant (p = 0.83). There were no differences in AX-ROM or LB-ROM ratios (p = 0.77 and 0.44, respectively). No failures were noted on fatigue testing of any EC construct (250,000 cycles). This was significantly improved compared with FSA (856 cycles, p < 0.001) and CS (794 cycles, p < 0.001). Conclusions The CS and EC appear to be significantly more stable constructs compared with FSA with FE-ROM. The 3 constructs appear to be equal with AX-ROM and LB-ROM. Most importantly, EC appears to be significantly more resistant to fatigue compared with FSA and CS. Reconstruction of the load transfer mechanism to the pelvis via the L-5 endplate appears to be important in maintenance of alignment after total sacrectomy reconstruction.

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Biomechanical evaluation of an integrated fixation cage during fatigue loading: a human cadaver study

Journal of Neurosurgery Spine ◽

10.3171/2016.9.spine16650 ◽

2017 ◽

Vol 26 (4) ◽

pp. 524-531 ◽

Cited By ~ 5

Author(s):

Vivek Palepu ◽

Jonathan H. Peck ◽

David D. Simon ◽

Melvin D. Helgeson ◽

Srinidhi Nagaraja

Keyword(s):

Mechanical Stability ◽

Fatigue Testing ◽

Plate Fixation ◽

Fatigue Loading ◽

Axial Rotation ◽

Cadaver Study ◽

Anterior Plate ◽

Stability Parameters ◽

Loading Mode ◽

Flexion Extension

OBJECTIVE Lumbar cages with integrated fixation screws offer a low-profile alternative to a standard cage with anterior supplemental fixation. However, the mechanical stability of integrated fixation cages (IFCs) compared with a cage with anterior plate fixation under fatigue loading has not been investigated. The purpose of this study was to compare the biomechanical stability of a screw-based IFC with a standard cage coupled with that of an anterior plate under fatigue loading. METHODS Eighteen functional spinal units were implanted with either a 4-screw IFC or an anterior plate and cage (AP+C) without integrated fixation. Flexibility testing was conducted in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) on intact spines, immediately after device implantation, and post-fatigue up to 20,000 cycles of FE loading. Stability parameters such as range of motion (ROM) and lax zone (LZ) for each loading mode were compared between the 2 constructs at multiple stages of testing. In addition, construct loosening was quantified by subtracting post-instrumentation ROM from post-fatigue ROM. RESULTS IFC and AP+C configurations exhibited similar stability (ROM and LZ) at every stage of testing in FE (p ≥ 0.33) and LB (p ≥ 0.23) motions. In AR, however, IFCs had decreased ROM compared with AP+C constructs at pre-fatigue (p = 0.07) and at all post-fatigue time points (p ≤ 0.05). LZ followed a trend similar to that of ROM in AR. ROM increased toward intact motion during fatigue cycling for AP+C and IFC implants. IFC specimens remained significantly (p < 0.01) more rigid than specimens in the intact condition during fatigue for each loading mode, whereas AP+C construct motion did not differ significantly (p ≥ 0.37) in FE and LB and was significantly greater (p < 0.01) in AR motion compared with intact specimens after fatigue. Weak to moderate correlations (R2 ≤ 56%) were observed between T-scores and construct loosening, with lower T-scores leading to decreased stability after fatigue testing. CONCLUSIONS These data indicate that a 4-screw IFC design provides fixation similar to that provided by an AP+C construct in FE and LB during fatigue testing and better stability in AR motion.

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New anterior controllable antedisplacement and fusion surgery for cervical ossification of the posterior longitudinal ligament: a biomechanical study

Journal of Neurosurgery Spine ◽

10.3171/2021.8.spine21879 ◽

2022 ◽

pp. 1-9

Keyword(s):

Fatigue Loading ◽

Axial Rotation ◽

Posterior Longitudinal Ligament ◽

Cyclic Fatigue ◽

Biomechanical Study ◽

Biomechanical Stability ◽

Loading Test ◽

Crossover Effect ◽

Flexion Extension

OBJECTIVE The traditional anterior approach for multilevel severe cervical ossification of the posterior longitudinal ligament (OPLL) is demanding and risky. Recently, a novel surgical procedure—anterior controllable antedisplacement and fusion (ACAF)—was introduced by the authors to deal with these problems and achieve better clinical outcomes. However, to the authors’ knowledge, the immediate and long-term biomechanical stability obtained after this procedure has never been evaluated. Therefore, the authors compared the postoperative biomechanical stability of ACAF with those of more traditional approaches: anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF). METHODS To determine and assess pre- and postsurgical range of motion (ROM) (2 Nm torque) in flexion-extension, lateral bending, and axial rotation in the cervical spine, the authors collected cervical areas (C1–T1) from 18 cadaveric spines. The cyclic fatigue loading test was set up with a 3-Nm cycled load (2 Hz, 3000 cycles). All samples used in this study were randomly divided into three groups according to surgical procedures: ACDF, ACAF, and ACCF. The spines were tested under the following conditions: 1) intact state flexibility test; 2) postoperative model (ACDF, ACAF, ACCF) flexibility test; 3) cyclic loading (n = 3000); and 4) fatigue model flexibility test. RESULTS After operations were performed on the cadaveric spines, the segmental and total postoperative ROM values in all directions showed significant reductions for all groups. Then, the ROMs tended to increase during the fatigue test. No significant crossover effect was detected between evaluation time and operation method. Therefore, segmental and total ROM change trends were parallel among the three groups. However, the postoperative and fatigue ROMs in the ACCF group tended to be larger in all directions. No significant differences between these ROMs were detected in the ACDF and ACAF groups. CONCLUSIONS This in vitro biomechanical study demonstrated that the biomechanical stability levels for ACAF and ACDF were similar and were both significantly greater than that of ACCF. The clinical superiority of ACAF combined with our current results showed that this procedure is likely to be an acceptable alternative method for multilevel cervical OPLL treatment.

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Hybrid dynamic stabilization: a biomechanical assessment of adjacent and supraadjacent levels of the lumbar spine

Journal of Neurosurgery Spine ◽

10.3171/2012.6.spine111054 ◽

2012 ◽

Vol 17 (3) ◽

pp. 232-242 ◽

Cited By ~ 18

Author(s):

Prasath Mageswaran ◽

Fernando Techy ◽

Robb W. Colbrunn ◽

Tara F. Bonner ◽

Robert F. McLain

Keyword(s):

Lumbar Spine ◽

Lumbar Fusion ◽

Industrial Robot ◽

Pedicle Screws ◽

Axial Rotation ◽

Dynamic Stabilization ◽

Follower Load ◽

Lateral Bending ◽

Intact Specimen ◽

Flexion Extension

Object The object of this study was to evaluate the effect of hybrid dynamic stabilization on adjacent levels of the lumbar spine. Methods Seven human spine specimens from T-12 to the sacrum were used. The following conditions were implemented: 1) intact spine; 2) fusion of L4–5 with bilateral pedicle screws and titanium rods; and 3) supplementation of the L4–5 fusion with pedicle screw dynamic stabilization constructs at L3–4, with the purpose of protecting the L3–4 level from excessive range of motion (ROM) and to create a smoother motion transition to the rest of the lumbar spine. An industrial robot was used to apply continuous pure moment (± 2 Nm) in flexion-extension with and without a follower load, lateral bending, and axial rotation. Intersegmental rotations of the fused, dynamically stabilized, and adjacent levels were measured and compared. Results In flexion-extension only, the rigid instrumentation at L4–5 caused a 78% decrease in the segment's ROM when compared with the intact specimen. To compensate, it caused an increase in motion at adjacent levels L1–2 (45.6%) and L2–3 (23.2%) only. The placement of the dynamic construct at L3–4 decreased the operated level's ROM by 80.4% (similar stability as the fusion at L4–5), when compared with the intact specimen, and caused a significant increase in motion at all tested adjacent levels. In flexion-extension with a follower load, instrumentation at L4–5 affected only a subadjacent level, L5–sacrum (52.0%), while causing a reduction in motion at the operated level (L4–5, −76.4%). The dynamic construct caused a significant increase in motion at the adjacent levels T12–L1 (44.9%), L1–2 (57.3%), and L5–sacrum (83.9%), while motion at the operated level (L3–4) was reduced by 76.7%. In lateral bending, instrumentation at L4–5 increased motion at only T12–L1 (22.8%). The dynamic construct at L3–4 caused an increase in motion at T12–L1 (69.9%), L1–2 (59.4%), L2–3 (44.7%), and L5–sacrum (43.7%). In axial rotation, only the placement of the dynamic construct at L3–4 caused a significant increase in motion of the adjacent levels L2–3 (25.1%) and L5–sacrum (31.4%). Conclusions The dynamic stabilization system displayed stability characteristics similar to a solid, all-metal construct. Its addition of the supraadjacent level (L3–4) to the fusion (L4–5) did protect the adjacent level from excessive motion. However, it essentially transformed a 1-level lumbar fusion into a 2-level lumbar fusion, with exponential transfer of motion to the fewer remaining discs.

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Sacral tumor resection and the impact on pelvic incidence

Journal of Neurosurgery Spine ◽

10.3171/2010.9.spine09728 ◽

2011 ◽

Vol 14 (1) ◽

pp. 78-84 ◽

Cited By ~ 10

Author(s):

Oren N. Gottfried ◽

Ibrahim Omeis ◽

Vivek A. Mehta ◽

Can Solakoglu ◽

Ziya L. Gokaslan ◽

...

Keyword(s):

Pelvic Incidence ◽

Tumor Resection ◽

Surgical Techniques ◽

Clinical Importance ◽

Johns Hopkins Hospital ◽

En Bloc ◽

Sacral Tumor ◽

Si Joint ◽

The Impact ◽

Total Sacrectomy

Object Pelvic incidence (PI) directly regulates lumbar lordosis and is a key determinant of sagittal spinal balance in normal and diseased states. Pelvic incidence is defined as the angle between the line perpendicular to the S-1 endplate at its midpoint and the line connecting this point to a line bisecting the center of the femoral heads. It reflects an anatomical value that increases with growth during childhood but remains constant in adulthood. It is not altered by changes in patient position or after traditional lumbosacral spinal surgery. There are only 2 reports of PI being altered in adults, both in cases of sacral fractures resulting in lumbopelvic dissociation and sacroiliac (SI) joint instability. En bloc sacral amputation and sacrectomy are surgical techniques used for resection of certain bony malignancies of the sacrum. High, mid, and low sacral amputations result in preservation of some or the entire SI joint. Total sacrectomy results in complete disruption of the SI joint. The purpose of this study was to determine if PI is altered as a result of total or subtotal sacral resection. Methods The authors reviewed a series of 42 consecutive patients treated at The Johns Hopkins Hospital between 2004 and 2009 for sacral tumors with en bloc resection. The authors evaluated immediate pre- and postoperative images for modified pelvic incidence (mPI) using the L-5 inferior endplate, as the patients undergoing a total sacrectomy are missing the S-1 endplate postoperatively. The authors compared the results of total versus subtotal sacrectomies. Results Twenty-two patients had appropriate images to measure pre- and postoperative mPI; 17 patients had high, mid, or low sacral amputations with sparing of some or the entire SI joint, and 5 patients underwent a total sacrectomy, with complete SI disarticulation. The mean change in mPI was statistically different (p < 0.001) for patients undergoing subtotal versus those undergoing total sacrectomy (1.6° ± 0.9° vs 13.6° ± 4.9° [± SD]). There was no difference between patients who underwent a high sacral amputation (partial SI resection, mean 1.6°) and mid or low sacral amputation (SI completely intact, mean 1.6°). Conclusions The PI is altered during total sacrectomy due to complete disarticulation of the SI joint and discontinuity of the spine and pelvis, but it is not changed if any of the joint is preserved. Changes in PI influence spinopelvic balance and may have postoperative clinical importance. Thus, the authors encourage attention to spinopelvic alignment during lumbopelvic reconstruction and fixation after tumor resection. Long-term studies are needed to evaluate the impact of the change in PI on sagittal balance, pain, and ambulation after total sacrectomy.

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FUNCTION OF THE MENISCI IN THE LOAD TRANSFER WITHIN THE KNEE JOINT

Tribologia ◽

10.5604/01.3001.0012.7537 ◽

2018 ◽

Vol 280 (4) ◽

pp. 81-88

Author(s):

Andrzej RYNIEWICZ ◽

Anna M. RYNIEWICZ ◽

Tomasz MACHNIEWICZ ◽

Łukasz BOJKO ◽

Wojciech RYNIEWICZ

Keyword(s):

Knee Joint ◽

Load Transfer ◽

Fatigue Testing ◽

Axial Loading ◽

Fatigue Loading ◽

Strength Analysis ◽

Cyclic Compression ◽

Joint Deformity ◽

Lubrication Conditions

The aim of the study was to conduct strength analysis of a knee joint in order to experimentally determine the destructive fatigue loading under the conditions of cyclic compression. Animal joints were used as the study material. They were periodically subjected to variable axial loading. The degree of joint deformity and damage to articular surfaces and menisci were globally determined after isolation of the joint structures. The application of the variant of axial loading without slip and rolling results in the rupture of the medial meniscus, which is an important biotribological structure. Fatigue testing of the joints allowed for the determination of the parameters of biomechanical extortions, which lead to the loss of normal lubrication conditions and the degradation of the meniscus and cartilage structures on the femoral condyles.

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Mechanical Characterization of a Viscoelastic Disc for Lumbar Total Disc Replacement

Journal of Medical Devices ◽

10.1115/1.4003536 ◽

2011 ◽

Vol 5 (1) ◽

Cited By ~ 5

Author(s):

Edward C. Benzel ◽

Isador H. Lieberman ◽

E. Raymond Ross ◽

Raymond J. Linovitz ◽

James Kuras ◽

...

Keyword(s):

Fatigue Testing ◽

Lumbar Disc ◽

Total Disc Replacement ◽

Axial Rotation ◽

Disc Replacement ◽

Constrained Motion ◽

Healthy Human ◽

Worst Case ◽

Lumbar Total Disc Replacement ◽

Flexion Extension

A viscoelastic artificial disc may more closely replicate normal stiffness characteristics of the healthy human disc compared with first-generation total disc replacement (TDR) devices, which do not utilize viscoelastic materials and are based on a ball and socket design that does not allow loading compliance. Mechanical testing was performed to characterize the durability and range of motion (ROM) of an investigational viscoelastic TDR (VTDR) device for the lumbar spine, the Freedom® Lumbar Disc. ROM data were compared with data reported for the human lumbar disc in the clinical literature. Flexibility and stiffness of the VTDR in compression, rotation, and flexion/extension were within the parameters associated with the normal human lumbar disc. The device constrained motion to physiologic ranges and replicated normal stress/strain dynamics. No mechanical or functional failures occurred within the loads and ROM experienced by the human disc. Fatigue testing of the worst case VTDR device size demonstrated a fatigue life of 50 years of simulated walking and 240 years of simulated significant bends in both flexion/extension and lateral bending coupled with axial rotation, with no functional failures. These results indicate that the VTDR evaluated in this mechanical study is durable and has the ability to replicate the stiffness and mechanics of the natural, healthy human lumbar disc.

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Construct Rigidity after Fatigue Loading in Pedicle Subtraction Osteotomy with or without Adjacent Interbody Structural Cages

Global Spine Journal ◽

10.1055/s-0032-1331460 ◽

2012 ◽

Vol 2 (4) ◽

pp. 213-220 ◽

Cited By ~ 15

Author(s):

Vedat Deviren ◽

Jessica A. Tang ◽

Justin K. Scheer ◽

Jenni M. Buckley ◽

Murat Pekmezci ◽

...

Keyword(s):

Dynamic Stiffness ◽

Fatigue Loading ◽

Axial Rotation ◽

Pedicle Subtraction Osteotomy ◽

Posterior Fixation ◽

Bending Rigidity ◽

Acute Setting ◽

Flexion Extension ◽

Extreme Lateral Interbody Fusion ◽

Lateral Interbody

Introduction Studies document rod fracture in pedicle subtraction osteotomy (PSO) settings where disk spaces were preserved above or adjacent to the PSO. This study compares the multidirectional bending rigidity and fatigue life of PSO segments with or without interbody support. Methods Twelve specimens received bilateral T12–S1 posterior fixation and L3 PSO. Six received extreme lateral interbody fusion (XLIF) cages in addition to PSO at L2–L3 and L3–L4; six had PSO only. Flexion-extension, lateral bending, and axial rotation (AR) tests were conducted up to 7.5 Newton-meters (Nm) for groups: (1) posterior fixation, (2) L3 PSO, (3) addition of cages (six specimens). Relative motion across the osteotomy (L2–L4) and entire fixation site (T12–S1) was measured. All specimens were then fatigue tested for 35K cycles. Results Regardingmultiaxial bending, there was a significant 25.7% reduction in AR range of motion across L2–L4 following addition of cages. Regarding fatigue bending, dynamic stiffness, though not significant ( p = 0.095), was 22.2% greater in the PSO + XLIF group than in the PSO-only group. Conclusions Results suggest that placement of interbody cages in PSO settings has a potential stabilizing effect, which is modestly evident in the acute setting. Inserting cages in a second-stage surgery remains a viable option and may benefit patients in terms of recovery but additional clinical studies are necessary to confirm this.

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Biomechanical analysis of occipitocervical stabilization techniques: emphasis on integrity of osseous structures at the occipital implantation sites

Journal of Neurosurgery Spine ◽

10.3171/2020.1.spine191331 ◽

2020 ◽

Vol 33 (2) ◽

pp. 138-147

Author(s):

Bryan W. Cunningham ◽

Kyle B. Mueller ◽

Kenneth P. Mullinix ◽

Xiaolei Sun ◽

Faheem A. Sandhu

Keyword(s):

Fatigue Testing ◽

Plate Fixation ◽

Axial Rotation ◽

Biomechanical Analysis ◽

Lateral Bending ◽

Mineral Density ◽

Plate Group ◽

Significant Difference ◽

Flexion Extension ◽

Implantation Sites

OBJECTIVEThe objective of the current study was to quantify and compare the multidirectional flexibility properties of occipital anchor fixation with conventional methods of occipitocervical screw fixation using nondestructive and destructive investigative methods.METHODSFourteen cadaveric occipitocervical specimens (Oc–T2) were randomized to reconstruction with occipital anchors or an occipital plate and screws. Using a 6-degree-of-freedom spine simulator with moments of ± 2.0 Nm, initial multidirectional flexibility analysis of the intact and reconstructed conditions was performed followed by fatigue loading of 25,000 cycles of flexion-extension (x-axis, ± 2.0 Nm), 15,000 cycles of lateral bending (z-axis, ± 2.0 Nm), and 10,000 cycles of axial rotation (y-axis, ± 2.0 Nm). Fluoroscopic images of the implantation sites were obtained before and after fatigue testing and placed on an x-y coordinate system to quantify positional stability of the anchors and screws used for reconstruction and effect, if any, of the fatigue component. Destructive testing included an anterior flexural load to construct failure. Quantification of implant, occipitocervical, and atlantoaxial junction range of motion is reported as absolute values, and peak flexural failure moment in Newton-meters (Nm).RESULTSAbsolute value comparisons between the intact condition and 2 reconstruction groups demonstrated significant reductions in segmental flexion-extension, lateral bending, and axial rotation motion at the Oc–C1 and C1–2 junctions (p < 0.05). The average bone mineral density at the midline keel (1.422 g/cm3) was significantly higher compared with the lateral occipital region at 0.671 g/cm3 (p < 0.05). There were no significant differences between the occipital anchor and plate treatments in terms of angular rotation (degrees; p = 0.150) or x-axis displacement (mm; p = 0.572), but there was a statistically significant difference in y-axis displacement (p = 0.031) based on quantitative analysis of the pre- and postfatigue fluoroscopic images (p > 0.05). Under destructive anterior flexural loading, the occipital anchor group failed at 90 ± 31 Nm, and the occipital plate group failed at 79 ± 25 Nm (p > 0.05).CONCLUSIONSBoth reconstructions reduced flexion-extension, lateral bending, and axial rotation at the occipitocervical and atlantoaxial junctions, as expected. Flexural load to failure did not differ significantly between the 2 treatment groups despite occipital anchors using a compression-fit mechanism to provide fixation in less dense bone. These data suggest that an occipital anchor technique serves as a biomechanically viable clinical alternative to occipital plate fixation.

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A comprehensive biomechanical analysis of sacral alar iliac fixation: an in vitro human cadaveric model

Journal of Neurosurgery Spine ◽

10.3171/2018.8.spine18328 ◽

2019 ◽

Vol 30 (3) ◽

pp. 367-375 ◽

Cited By ~ 4

Author(s):

Bryan W. Cunningham ◽

Paul D. Sponseller ◽

Ashley A. Murgatroyd ◽

Jun Kikkawa ◽

P. Justin Tortolani

Keyword(s):

Sacroiliac Joint ◽

Fatigue Loading ◽

Axial Rotation ◽

Biomechanical Analysis ◽

Segmental Motion ◽

Destructive Testing ◽

Flexion Extension ◽

Iliac Screws ◽

Iliac Fixation

OBJECTIVEThe objective of the current study was to quantify and compare the multidirectional flexibility properties of sacral alar iliac fixation with conventional methods of sacral and sacroiliac fixation by using nondestructive and destructive investigative methods.METHODSTwenty-one cadaveric lumbopelvic spines were randomized into 3 groups based on reconstruction conditions: 1) S1–2 sacral screws; 2) sacral alar iliac screws; and 3) S1–iliac screws tested under unilateral and bilateral fixation. Nondestructive multidirectional flexibility testing was performed using a 6-degree-of-freedom spine simulator with moments of ± 12.5 Nm. Flexion-extension fatigue loading was then performed for 10,000 cycles, and the multidirectional flexibility analysis was repeated. Final destructive testing included an anterior flexural load to construct failure. Quantification of the lumbosacral and sacroiliac joint range of motion was normalized to the intact spine (100%), and flexural failure loads were reported in Newton-meters.RESULTSNormalized value comparisons between the intact spine and the 3 reconstruction groups demonstrated significant reductions in segmental flexion-extension, lateral bending, and axial rotation motion at L4–5 and L5–S1 (p < 0.05). The S1–2 sacral reconstruction group demonstrated significantly greater flexion-extension motion at the sacroiliac junction than the intact and comparative reconstruction groups (p < 0.05), whereas the sacral alar iliac group demonstrated significantly less motion at the sacroiliac joint in axial rotation (p < 0.05). Absolute value comparisons demonstrated similar findings. Under destructive anterior flexural loading, the S1–2 sacral group failed at 105 ± 23 Nm, and the sacral alar iliac and S1–iliac groups failed at 119 ± 39 Nm and 120 ± 28 Nm, respectively (p > 0.05).CONCLUSIONSAlong with difficult anatomy and weak bone, the large lumbosacral loads with cantilever pullout forces in this region are primary reasons for construct failure. All reconstructions significantly reduced flexibility at the L5–S1 junctions, as expected. Conventional S1–2 sacral fixation significantly increased sacroiliac motion under all loading modalities and demonstrated significantly higher flexion-extension motion than all other groups, and sacral alar iliac fixation reduced motion in axial rotation at the sacroiliac joint. Based on comprehensive multidirectional flexibility testing, the sacral alar iliac fixation technique reduced segmental motion under some loading modalities compared to S1–iliac screws and offers potential advantages of lower instrumentation profile and ease of assembly compared to conventional sacroiliac instrumentation techniques.

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Prevention of facial pressure ulcers using the Mayfield clamp for sacral tumor resection

Journal of Neurosurgery Spine ◽

10.3171/2010.9.spine09516 ◽

2011 ◽

Vol 14 (1) ◽

pp. 85-87 ◽

Cited By ~ 9

Author(s):

C. Rory Goodwin ◽

Pablo F. Recinos ◽

Ibrahim Omeis ◽

Eric N. Momin ◽

Timothy F. Witham ◽

...

Keyword(s):

Prone Position ◽

Surgical Procedures ◽

Operative Time ◽

Pressure Ulcers ◽

Tumor Resection ◽

Tissue Necrosis ◽

Sacral Tumor ◽

Time Required ◽

Total Sacrectomy ◽

Visible Area

Sacral neoplasm resection is managed via partial or total sacrectomy that is performed via the Kraske approach. The combination of the patients positioning and the relatively long operative time required for this procedure increase the risk of pressure ulcers. Facial pressure ulcers can cause tissue necrosis and/or ulceration in a highly visible area, leading to a cosmetically disfiguring lesion. Here, the authors report the use of a Mayfield clamp in the positioning of patients undergoing sacral tumor resection to prevent facial pressure ulceration. After the patient is placed prone in the Kraske or Jackknife position, the hips and knees are flexed with arms to the side. Then while in the prone position, the patient is physically placed in pins, and the Mayfield clamp is fixated at the center of the metal arch via the Mayfield sitting adapter to the Andrews frame, suspending the head (and face) over the table. The authors find that this technique prevents the development of facial pressure ulcers, and it has the potential to be used in patients positioned in the Kraske position for other surgical procedures.

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