Gait changes as the result of deformity reconstruction surgery in a group of adults with lumbar scoliosis

Longitudinal impact of multi-segment spinal fixation surgery on mobility status and clinical outcomes in adult spinal deformity: a multicenter retrospective study

PURPOSE

To investigate changes in postoperative mobility status in patients with ASD, and the determining factors that influence these changes and their impact on clinical outcomes, including the rate of home discharge and long-term mobility.

METHODS

A total of 299 patients with ASD who underwent multi-segment posterior spinal fusion were registered in a multi-center database were investigated. Patient mobility status was assessed using walking aids and classified into five levels (1: independent, 2: cane, 3: walker, 4: assisted, and 5: wheelchair) preoperatively, at discharge, and after 2 years. We determined improvements or declines in the patient's mobility based on changes in the classification levels. The analysis focused on the factors contributing to the deterioration of postoperative mobility.

RESULTS

Two years postoperatively, 87% of patients maintained or improved mobility. However, 27% showed decreased mobility status at discharge, associated with a lower rate of home discharge (49% vs. 80% in the maintained mobility group) and limited improvement in mobility status (35% vs. 5%) after 2 years. Notably, postoperative increases in thoracic kyphosis (7.0 ± 12.1 vs. 2.0 ± 12.4°, p = 0.002) and lower lumbar lordosis (4.2 ± 13.1 vs. 1.8 ± 12.6°, p = 0.050) were substantial factors in mobility decline.

CONCLUSION

Postoperative mobility often temporarily decreases but generally improves after 2 years. However, an overcorrection in sagittal alignment, evidenced by increased TK, could detrimentally affect patients' mobility status. Transient mobility decline associated with overcorrection may require further rehabilitation or hospitalization. Further studies are required to determine the biomechanical effects of surgical correction on mobility.

Impact of Self-Reported Loss of Balance and Gait Disturbance on Outcomes following Adult Spinal Deformity Surgery

Background: The objective of this study was to evaluate if imbalance influences complication rates, radiological outcomes, and patient-reported outcomes (PROMs) following adult spinal deformity (ASD) surgery. Methods: ASD patients with baseline and 2-year radiographic and PROMs were included. Patients were grouped according to whether they answered yes or no to a recent history of pre-operative loss of balance. The groups were propensity-matched by age, pelvic incidence-lumbar lordosis (PI-LL), and surgical invasiveness score. Results: In total, 212 patients were examined (106 in each group). Patients with gait imbalance had worse baseline PROM measures, including Oswestry disability index (45.2 vs. 36.6), SF-36 mental component score (44 vs. 51.8), and SF-36 physical component score (p < 0.001 for all). After 2 years, patients with gait imbalance had less pelvic tilt correction (-1.2 vs. -3.6°, p = 0.039) for a comparable PI-LL correction (-11.9 vs. -15.1°, p = 0.144). Gait imbalance patients had higher rates of radiographic proximal junctional kyphosis (PJK) (26.4% vs. 14.2%) and implant-related complications (47.2% vs. 34.0%). After controlling for age, baseline sagittal parameters, PI-LL correction, and comorbidities, patients with imbalance had 2.2-times-increased odds of PJK after 2 years. Conclusions: Patients with a self-reported loss of balance/unsteady gait have significantly worse PROMs and higher risk of PJK.

Activity and sports resumption after long segment fusions to the pelvis for adult spinal deformity: survey results of AO Spine members

PURPOSE

To assess recommendations for when adult spinal deformity (ASD) patients may return to athletic activities after surgery.

METHODS

A web-based survey was administered to members of AO Spine. The survey consisted of surgeon demographic information and questions asking when a patient undergoing a long thoracolumbar fusion (> 5 levels) with pelvic fixation for ASD would be allowed to resume unrestricted range of motion (ROM), non-contact sports, and contact sports postoperatively. Ordinal logistic regression was used to determine predictors for time to resume each activity.

RESULTS

One hundred twenty four members' responses were included for analysis. The majority of respondents would allow unrestricted ROM within 3 months postop (< 3 months: 81% vs > 3 months: 19%]. For when to return to non-contact sports, the most common responses were "2-3 months" (26.6%), "3-4 months" (26.6%), and "6-12 months" (18.5%). For when to return to contact sports, the majority advised > 4 months postop [> 4 months: "4-6 months" (19.2%), "6-12 months" (28.0%), " > 12 months" (28.8%) versus < 4 months: "1-2 months" (4.0%), "2-3 months" (1.6%), "3-4 months" (8.8%)]. 8.8% responded they would "never" allow resumption of contact sports.

CONCLUSION

There was significant variation between surgeons' recommendations for resumption of unrestricted range of motion and sports following long fusion with pelvic fixation for ASD. An evidence-based approach to activity recommendations will require information on outcomes and complications.

Relationship between gait parameter and spinal sagittal profiles in asymptomatic subjects

BACKGROUND

To study the gait parameters in asymptomatic volunteers and investigate the correlation between the gait and several radiographic sagittal profiles.

METHODS

Asymptomatic volunteers (20-50 years of age) were included and allocated into three subgroups depending on pelvic incidence (low, normal, and high). Standing whole spine radiographs and gait analysis data were obtained. The Pearson Coefficient Correlation was used to determine the relationship between the gait and radiographic profiles.

RESULTS

A total of 55 volunteers (28 male and 27 females) were included. The mean age was 27.35 ± 6.37 years old. The average sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), and PI-LL mismatch (PI-LL) were 37.78 ± 6.59, 14.51 ± 9.19 degrees, and 52.29 ± 10.87 degrees and - 0.36 ± 11.41, respectively. The mean velocity and stride of all the volunteers were 119.00 ± 30.12 cm/s and 130.25 ± 7.72 cm, correspondingly. The correlation between each of the radiographical and gait parameters was low (ranging from - 0.24 to 0.26).

CONCLUSION

Gait parameters were not differenced significantly between each of the PI subgroups in asymptomatic volunteers. Spinal sagittal parameters also showed a low correlation with gait parameters.

Spinopelvic movement strategies during sit-to-stand and stand-to-sit in adult spinal deformity

BACKGROUND

Research interest on the impact of adult spinal deformity (ASD) on spinopelvic and whole body motion has increased over the past years. Studies focusing on overground walking, showed that patients with ASD indeed present with functional impairments. Functional tasks challenging the spinopelvic complex, such as sit-to-stand-to-sit, might identify clinically relevant biomechanical parameters and could further increase our insights on how ASD impacts functioning and disability.

RESEARCH QUESTION

Do patients with ASD use different spinopelvic strategies during sit-to-stand (STSt) and stand-to-sit (StTS) compared to healthy controls?

METHODS

In this prospective study, marker-based motion analysis and a subject-specific polynomial fit were used to assess spinopelvic kinematics (thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis (SVA), trunk, pelvis) during STSt/StTS in 42 patients with ASD and 18 control subjects. All parameters were compared between controls and patients with ASD, divided in three groups based on their sagittal alignment (ASD 1: decompensated sagittal malalignment; ASD 2: compensated sagittal malalignment; ASD 3: scoliosis and normal sagittal alignment). Continuous kinematic and kinetic data were analyzed through statistical parametric mapping.

RESULTS

Patients with ASD showed decreased LL and increased trunk flexion and SVA during STSt/StTS compared to controls. These differences were mainly observed in sagittal deformity patients (ASD 1 and 2). In contrast, coronal patients (ASD 3) did not differ from controls. Dynamic LL and SVA significantly correlated with radiographic LL and SVA, however these relations decreased during the middle third of the motion cycle.

SIGNIFICANCE

Patients with ASD use aberrant spinopelvic strategies during STSt/StTS compared to healthy controls. Only partial correlation to static radiographic parameters suggests other mechanisms need to be identified in addition to spinal malalignment. These might include impaired neuromuscular control or muscle weakness. Further research on movement patterns during functional tasks might ultimately result in treatment strategies that aim to augment activity participation by targeting improvements in movement function.

Significance of long corrective fusion to the ilium for physical function in patients with adult spinal deformity

BACKGROUND

We aimed to investigate the impact of long corrective fusion to the ilium on the physical function in elderly patients with adult spinal deformity and its correlation with spinopelvic parameters and health-related quality of life outcomes.

METHODS

We included 60 female patients who underwent long corrective fusion from T9 or T10 to the pelvis for adult spinal deformities (mean age of 69.8 years, range 55-78 years). The radiographic parameters, health-related quality of life outcomes using the Scoliosis Research Society Outcome Instrument-22 and physical function assessments were reviewed preoperatively and at 1-year postoperatively.

RESULTS

All spinopelvic parameters, except for thoracolumbar kyphosis, and all domains of the Scoliosis Research Society Outcome Instrument-22 significantly improved at 1-year postoperatively (p < 0.0001). Physical function results, including those for one-leg standing time, timed up-and-go test, and 6-min walk tests, significantly improved at 1-year postoperatively (p < 0.005). Based on forward stepwise multivariate logistic regression, the predicted timed up-and-go test and 6-min walk test outcomes at 1-year postoperatively were as follows: timed up-and-go test, 7.8 + 0.47 × preoperative timed up-and-go test - 0.21 × 1-year postoperative grasping power +0.015 × 1-year postoperative C1 sagittal vertical axis (R2 = 0.6209, p < 0.0001); 6-min walk test, 309.2-9.1 × body mass index + 11.6 × 1-year postoperative grasping power + 3.3 × 1-year postoperative thoracolumbar kyphosis - 0.59 × 1-year postoperative C1 sagittal vertical axis (R2 = 0.4409, p < 0.0001).

CONCLUSIONS

Corrective long fusion surgery for adult spinal deformity in normalizing sagittal alignment improves trunk balance and gait performance. Postoperative physical function depends on the preoperative physical performance status and skeletal muscle status; thus, preoperative interventions for improved physical function are recommended.

Gait Kinetic and Kinematic Changes in Chronic Low Back Pain Patients and the Effect of Manual Therapy: A Randomized Controlled Trial

Patients with chronic back pain as a result of degenerated disc disease, besides pain, also present with impaired gait. The purpose of the article was to evaluate kinetic and kinematic characteristics during gait analysis in patients with chronic low back pain as a result of degenerated disc disease, before and after the application of physiotherapy, including manual therapy techniques. Seventy-five patients suffering from chronic low back pain were randomly divided into 3 groups of 25 each. Each group received five sessions (one per week) of interventions with the first group receiving manual therapy treatment, the second a sham treatment and the third, classic physiotherapy (stretching exercises, TENS and massage). The effectiveness of each treatment was evaluated using an optoelectronic system for recording and analysis of gait (kinetic and kinematic data). Patients overall showed an impaired gait pattern with a difference in kinetic and kinematic data between the left and the right side. Following the application of the above-named interventions, only the group that received manual therapy showed a tendency towards symmetry between the right and left side. In patients suffering from chronic low back pain as a result of degenerated disc disease, the application of five manual therapy sessions seems to produce a tendency towards symmetry in gait.

Reporting and tracking objective functional outcome measures: implementation of a summary report for gait and balance measures

The aim of this manuscript is to describe knowledge gaps in the literature, future directions, and emerging applications of gait and balance analysis in spine surgery with regard to functional outcomes measurement. Functional outcome measurement has been established as a useful clinical and research investigational tool in musculoskeletal disease. Evidence currently supports its use in the diagnosis, treatment, and outcome measurement of multiple musculoskeletal disease states, including spinal disease, and its usefulness continues to grow as literature develops. Gait and balance analysis has proven to be broadly applicable, but most clinicians remain unfamiliar and untrained in its usage. The logistical and communication barriers are also described with the potential solutions that are on the near horizon of research. This article describes our methodology for improving conveyance of functional outcome measures in spine surgery. Additionally, we provide a case example of an adult patient with spinal deformity who is examined pre and post operatively using our methodology.

Fear-avoidance and Patients' Reported Outcomes are Strongly Correlated With Biomechanical Gait Parameters in Cervical Spondylotic Myelopathy Patients

STUDY DESIGN

This was a prospective cohort study.

OBJECTIVE

The aim was to explores whether fear-avoidance is associated with altered gait patterns in cervical spinal myelopathy (CSM) patients.

SUMMARY OF BACKGROUND DATA

Fear-avoidance is associated with activity restriction and emotional distress in chronic pain patients and with poorer spine surgery outcomes. In adults with spinal deformity, fear and avoidance correlates with gait pattern disruptions. Patients having CSM also display distorted gait.

METHODS

Ninety CSM patients completed the Tampa Scale for Kinesiophobia (TSK) questionnaire, and the Fear-avoidance Beliefs Questionnaire (FABQ). Each patient performed a series of gait trials. Pearson's product correlation analysis was used to determine the relationship between the self-reported fear of movement measures and the objective gait biomechanical data.

RESULTS

The TSK total score was correlated with walking speed ( P =0.003), cadence ( P =0.012), stride ( P =0.010) and step ( P =0.036) time, and stride ( P =0.018) and step ( P =0.035) length. The FABQ physical dimension was correlated with walking speed ( P <0.001), cadence ( P <0.001), stride ( P <0.001) and step ( P =0.006) time, stride ( P <0.001) and step ( P <0.001) length, and gait deviation index ( P <0.001). The FABQ work dimension was correlated with walking speed ( P =0.001), cadence ( P =0.001), stride ( P =0.001) and step ( P =0.008) time, and stride ( P =0.014) and step ( P =0.002) length.

CONCLUSIONS

These results provide a framework for further investigation of the relationship between psychosocial factors and objectively measured function in patients with CSM. This study demonstrates a strong correlation between fear and avoidance of movement, as measured with the TSK and FABQ and multiple biomechanical gait parameters, as measured with gait analysis. The current results may imply that fear and avoidance may compound and worsen functional deficits arising from CSM, and strongly suggest that fear and avoidance beliefs should be included as a component of presurgical diagnostic process for CSM patients.

Representative dynamic ranges of spinal alignment during gait in patients with mild and severe adult spinal deformities

BACKGROUND CONTEXT

Surgical correction strategies for adult spinal deformity (ASD) relies heavily on radiographic alignment goals, however, there is often debate regarding degree of correction and how static alignment translates to physical ability in daily life. Kinematic analysis has the potential to improve the concept of ideal spinal alignment by providing clinically meaningful estimates of dynamic changes in spinal alignment during activities of daily life.

PURPOSE

Estimate representative dynamic ranges of spinal alignment during gait among ASD patients using 3D motion tracking; compare dynamic alignment between mild and severe deformity patients and to healthy adults.

STUDY DESIGN/SETTING

Retrospective review at a single institution.

PATIENT SAMPLE

Fifty-two ASD patients and 46 healthy adults.

OUTCOME MEASURES

Radiographic alignment, kinematic spine motion, spatiotemporal gait measures, patient reported outcomes (VAS pain, ODI, SRS-22r).

METHODS

Spinal alignment was assessed radiographically and during standing and overground walking tests. Dynamic alignment was initialized by linking radiographic alignment to kinematic alignment during standing and at initial heel contact during gait. Dynamic changes in maximums and minimums during gait were made relative to initial heel contact for each gait cycle. Total range-of-motion (RoM) was measured for both ASD and healthy subjects. Dynamic alignment measures included coronal and sagittal vertical axes (CVA, SVA), T1 pelvic angle (TPA), lumbar lordosis (LL), and pelvic tilt (PT). ASD patient's deformities were classified as either Mild or Severe based on the SRS-Schwab ASD classification.

RESULTS

Severe ASD patients had significantly larger dynamic maximum and minimums for SVA, TPA, LL, and PT (all p<.05) compared with Mild ASD patients. ASD patients exhibited little difference in dynamic alignment compared with healthy subjects. Only PT had a significant difference in dynamic RoM compared with healthy (p<.001).

CONCLUSIONS

Mild and Severe ASD patients exhibited similar global dynamic alignment measures during gait and had comparable RoM to healthy subjects except with greater PT and reduced spatiotemporal performance which may be key compensatory mechanisms for dynamic stabilization.

Improvement in Gait Pattern and its Relationship With Preoperative Pelvic Compensation After Surgery in Patients With Sagittal Plane Deformity

STUDY DESIGN

Prospective observational study.

OBJECTIVE

The aim of this study was to investigate the improvement in gait parameters after surgery and whether corrective surgery for sagittal imbalance would be influenced by preoperative pelvic compensation.

SUMMARY OF BACKGROUND DATA

There have been no other studies investigating the influence of preoperative pelvic compensation on surgical outcomes.

METHODS

A total of 32 patients who were scheduled to undergo corrective surgery for sagittal plane deformity were included and were followed-up for 1 year after surgery. Radiological parameters were measured on biplanar full-body imaging. Before surgery and 6 months after surgery, three-dimensional motion analyses were performed to estimate center of gravity (CoG) deviation from the center of mass (CoM), mean trunk kyphosis (TK) angle, gait deviation index (GDI), and kinematic parameters. Before surgery, the patients were classified into CoG+ and CoG- groups. "+" and "-" representing increases and decreases in the distance of CoG from CoM of the pelvic segment from first to third trials, respectively. Oswestry Disability Index (ODI) and EuroQol-5D (EQ-5D) were measured for 1 year after surgery.

RESULTS

All radiological parameters improved significantly after surgery. For gait parameters, CoG from CoM, mean TK angle, and minimum angle of the hip and knee joints in the stance phase during walking were significantly decreased after surgery and GDI scores significantly improved after surgery. The mean changes of the CoG distance from the CoG and the mean TK from first to third trials of gait analysis significantly decreased postoperatively. There were no significant differences in ODI and EQ-5D scores over 1-year follow-up assessment between CoG+ and CoG- groups.

CONCLUSION

Preoperative abnormal stooping gait, and progressive worsening of sagittal imbalance in patients with sagittal plane deformity improved after corrective surgery. Patients with preoperative dynamic sagittal imbalance could have similar surgical results to those without it after corrective surgery.

LEVEL OF EVIDENCE

3.

Characteristics and treatment of dynamic sagittal imbalance in adult spinal deformity

OBJECTIVE

To raise the diagnostic criteria, classification and treatment strategy of dynamic sagittal imbalance (DSI).

METHODS

One hundred thirty-three adult spinal deformity (ASD) patients with stooping and back pain after walking were retrospectively analyzed. Based on the radiographic parameters and Oswestry Disability Index (ODI) scores, the diagnostic criteria of DSI were raised. DSI patients received nonoperative treatment and (or) surgery. Radiographic parameters and health-related quality of life (HRQOL) outcomes would be measured and compared between prewalk and postwalk and among each subgroup.

RESULTS

One hundred thirty-three ASD patients with stooping and back pain after walking were enrolled in our study. The quantitative diagnostic criteria was prewalk SVA < 40 mm and postwalk SVA-prewalk SVA ≥ 20 mm after 10-min walk. Based on the quantitative diagnostic criteria of DSI raised by our team, DSI patients could be classified into three groups: 20 mm ≤ ΔSVA < 60 mm (mild, 31.0%), 60 mm ≤ ΔSVA < 100 mm (moderate, 42.1%) and ΔSVA ≥ 100 mm (severe, 27.0%). After nonoperative treatment, the ΔSVA in mild and moderate group was prominently decreased (P < 0.001) with the significant improvement of HRQOL outcomes (P < 0.001), while there was no significant change in ΔSVA and clinical outcomes in group C (P > 0.05). Patients who received the operative treatment showed prominent improvement in ΔSVA and clinical outcomes (P < 0.001).

CONCLUSION

Our study proposed a quantitative diagnostic criteria and novel classification of DSI. Nonoperative treatment is effective for most DSI patients with ΔSVA < 100 mm, while the majority of DSI patients with ΔSVA ≥ 100 mm need operative intervention.

Spatial and temporal characteristics of the spine muscles activation during walking in patients with lumbar instability due to degenerative lumbar disk disease: Evaluation in pre-surgical setting

Our purpose was to investigate the spatial and temporal profile of the paraspinal muscle activation during gait in a group of 13 patients with lumbar instability (LI) in a pre-surgical setting compared to the results with those from both 13 healthy controls (HC) and a sample of 7 patients with failed back surgery syndrome (FBSS), which represents a chronic untreatable condition, in which the spine muscles function is expected to be widely impaired. Spatiotemporal gait parameters, trunk kinematics, and muscle activation were measured through a motion analysis system integrated with a surface EMG device. The bilateral paraspinal muscles (longissimus) at L3-L4, L4-L5, and L5-S1 levels and lumbar iliocostalis muscles were evaluated. Statistical analysis revealed significant differences between groups in the step length, step width, and trunk bending and rotation. As regard the EMG analysis, significant differences were found in the cross-correlation, full-width percentage and center of activation values between groups, for all muscles investigated. Patients with LI, showed preserved trunk movements compared to HC but a series of EMG abnormalities of the spinal muscles, in terms of left-right symmetry, top-down synchronization, and spatiotemporal activation and modulation compared to the HC group. In patients with LI some of such EMG abnormalities regarded mainly the segment involved by the instability and were strictly correlated to the pain perception. Conversely, in patients with FBSS the EMG abnormalities regarded all the spinal muscles, irrespective to the segment involved, and were correlated to the disease's severity. Furthermore, patients with FBSS showed reduced lateral bending and rotation of the trunk and a reduced gait performance and balance. Our methodological approach to analyze the functional status of patients with LI due to spine disease with surgical indications, even in more complex conditions such as deformities, could allow to evaluate the biomechanics of the spine in the preoperative conditions and, in the future, to verify whether and which surgical procedure may either preserve or improve the spine muscle function during gait.

ISSLS PRIZE IN BIOENGINEERING SCIENCE 2019: biomechanical changes in dynamic sagittal balance and lower limb compensatory strategies following realignment surgery in adult spinal deformity patients

STUDY DESIGN

A longitudinal cohort study.

OBJECTIVE

To define a set of objective biomechanical metrics that are representative of adult spinal deformity (ASD) post-surgical outcomes and that may forecast post-surgical mechanical complications. Current outcomes for ASD surgical planning and post-surgical assessment are limited to static radiographic alignment and patient-reported questionnaires. Little is known about the compensatory biomechanical strategies for stabilizing sagittal balance during functional movements in ASD patients.

METHODS

We collected in-clinic motion data from 15 ASD patients and 10 controls during an unassisted sit-to-stand (STS) functional maneuver. Joint motions were measured using noninvasive 3D depth mapping sensor technology. Mathematical methods were used to attain high-fidelity joint-position tracking for biomechanical modeling. This approach provided reliable measurements for biomechanical behaviors at the spine, hip, and knee. These included peak sagittal vertical axis (SVA) over the course of the STS, as well as forces and muscular moments at various joints. We compared changes in dynamic sagittal balance (DSB) metrics between pre- and post-surgery and then separately compared pre- and post-surgical data to controls.

RESULTS

Standard radiographic and patient-reported outcomes significantly improved following realignment surgery. From the DSB biomechanical metrics, peak SVA and biomechanical loads and muscular forces on the lower lumbar spine significantly reduced following surgery (- 19 to - 30%, all p < 0.05). In addition, as SVA improved, hip moments decreased (- 28 to - 65%, all p < 0.05) and knee moments increased (+ 7 to + 28%, p < 0.05), indicating changes in lower limb compensatory strategies. After surgery, DSB data approached values from the controls, with some post-surgical metrics becoming statistically equivalent to controls.

CONCLUSIONS

Longitudinal changes in DSB following successful multi-level spinal realignment indicate reduced forces on the lower lumbar spine along with altered lower limb dynamics matching that of controls. Inadequate improvement in DSB may indicate increased risk of post-surgical mechanical failure. These slides can be retrieved under Electronic Supplementary Material.

Gait Alteration in Cervical Spondylotic Myelopathy Elucidated by Ground Reaction Forces

STUDY DESIGN

.: Prospective cohort study.

OBJECTIVE

.: Analyze GRF parameters in cervical spondylotic myelopathy (CSM) patients to elucidate gait alterations as compared with healthy controls.

SUMMARY OF BACKGROUND DATA

.: During the human gait cycle, the magnitude and direction of the force each foot imparts on the ground varies in a controlled fashion to propel the body's center of mass forward. Alterations in GRF patterns can both point to subtle gait disturbances and explain altered gait patterns such as that seen in CSM.

METHODS

.: Thirty-two patients with symptomatic CSM who have been scheduled for surgery, along with 30 healthy controls (HC), underwent clinical gait analysis a week before surgery. Vertical GRF parameters and force magnitude and timing at various points of the gait cycle (i.e., heel contact, maximum weight acceptance, mid-stance, and push off) were analyzed and compared between groups.

RESULTS

.: Increased heel contact (CSM: 60.13% vs. HC: 27.82% of body weight, BW,P = 0.011), maximum weight acceptance (CSM: 120.13% vs. HC: 100.97% of BW, P = 0.016), and diminished push off (CSM: 91.35% vs. HC: 106.54% of BW, P = 0.001) forces were discovered in CSM patients compared with HC. Compared with controls CSM patients had delayed heel contact (CSM: 9.32% vs. HC: 5.12% of gait cycle, P = 0.050) and earlier push off (CSM: 54.96% vs. HC: 59.0% of gait cycle, P = 0.050), resulting in a shorter stance phase.

CONCLUSION

.: This study reinforces how CSM patients commonly exhibit altered gait patterns, but also uniquely demonstrates the increased heel-contract and maximum weight acceptance forces, diminished toe-off forces, and the shorter stance phase to absorb the BW load. When examined from a global perspective, these altered GRF parameters reflect the difficulty CSM patients have with catching their center of mass during heel-contact to avoid falling and with subsequently propelling themselves forward.

LEVEL OF EVIDENCE

3.

Efficacy of Corrective Surgery for Gait and Energy Expenditure in Patients with Scoliosis: A Literature Review

The aim of this literature review was to evaluate selected original papers that measured gait parameters and energy expenditure in idiopathic scoliosis (IS) treated with surgical intervention. IS is a progressive growth disease that affects spinal anatomy, mobility, and left–right trunk symmetry. Consequently, IS can modify human gait. Spinal fusions remain the primary approach to correcting scoliosis deformities, thereby halting progression. Using the population intervention comparison outcome measure framework and selected keywords, 15 studies that met the inclusion criteria were selected. Alteration of spatial and temporal variables in patients with IS was contradictory among the selected studies. Ankle and foot kinematics did not change after surgery; however, pelvic and hip frontal motions increased and pelvic rotation decreased following surgery. Patients with IS continued to show excessive energy expenditure following surgery in the absence of a physical rehabilitation protocol. Spinal surgery may be considered for gait improvement and IS treatment. There were inadequate data regarding the effect of corrective surgery on the kinetics, energy expenditure, and muscle activity parameters.

The use of gait analysis in the assessment of patients afflicted with spinal disorders

PURPOSE

Use gait analysis to establish and detail the clinically relevant components of normal human gait, analyze the gait characteristics for those afflicted with spinal pathology, and identify those aspects of human gait that correlate with pre- and postoperative patient function and outcomes.

METHODS

Twenty patients with adult degenerative scoliosis (ADS), 20 patients with cervical spondylotic myelopathy (CSM), and 15 healthy volunteers performed over-ground gait trials with a comfortable self-selected speed using video cameras to measure patient motion, surface electromyography (EMG) to record muscle activity, and force plates to record ground reaction force (GRF). Gait distance and temporal parameters, ankle, knee, hip, pelvic, and trunk range of motion (ROM), duration of lower extremity EMG activity and peak vertical GRF were measured.

RESULTS

Patients with ADS and CSM exhibited a significantly slower gait speed, decrease in step length, cadence, longer stride time, stance time, double support time, and an increase in step width compared to those in the control group. These patients also exhibited a significantly different ankle, knee, pelvic, and trunk ROM. Moreover, spinal disorder patients exhibited a significantly longer duration of rectus femoris, semitendinosus, tibialis anterior and medial gastrocnemius muscle activity along with an altered vertical GRF pattern.

CONCLUSIONS

Gait analysis provides an objective measure of functional gait in healthy controls as well as those with ADS and CSM. This study established and detailed some of the important kinematic and kinetic variables of gait in patients with spinal disorders. We recommend that spine care providers use gait analysis as part of their clinical evaluation to provide an objective measure of function. These slides can be retrieved under Electronic Supplementary Material.

Effect of the upper instrumented vertebral level (upper vs. lower thoracic spine) on gait ability after corrective surgery for adult spinal deformity

BACKGROUND CONTEXT

The relationship between gait pattern and the level of upper instrumented vertebra (UIV) in surgically treated patients with adult spinal deformity (ASD) has not been fully documented.

PURPOSE

This study aimed to assess the effect of UIV level for the gait pattern in ASD.

STUDY DESIGN/SETTING

A prospective case series was carried out.

PATIENT SAMPLE

Thirty surgically treated consecutive female ASD with lumbosacral fusion (age 67.0±8.4 years; body mass index 22.7±2.4 kg/m²; Cobb angle 49.9°±21.3°; coronal vertical axis 1.5±3.6 cm; C7 sagittal vertical axis [C7SVA] 9.3±5.3 cm; pelvic incidence-lumbar lordosis 35.4°±25.8°; and lean volume of the lower leg 5.5±0.9 kg) were categorized into upper thoracic [UT] group or lower thoracic [LT] group based on the level of UIV (UT; UIV T2-T5, LT; UIV T9-T11), and the gait pattern were compared before and after corrective spine surgery.

OUTCOME MEASURES

Scoliosis Research Society Patient Questionnaire, Oswestry Disability Index, and force plate analysis were the outcome measures.

METHODS

All subjects underwent gait analysis on a custom-built force plate. Dual-energy X-ray absorptiometry. Subjects were followed-up for at least 2 years postoperation.

RESULTS

The UT group had larger baseline Cobb angle, whereas the LT group had larger C7SVA (UT vs. LT; Cobb angle: 59.2±22.9 vs. 44.6±17.4°, p=.03, C7SVA: 10.9±8.7 vs. 12.0±7.1 cm, p=.03). Preoperatively, no difference was found in gait velocity and stride between UT and LT group, whereas the right and left difference of step length was significantly large in UT group (velocity: 55.0±12.5 vs. 53.6±9.0 m/min, stride: 99.7±13.0 vs. 97.8±13.6 cm, step length; 10.4±4.9 vs. 5.6%±3.3%). Coronal and sagittal alignments were significantly improved in both groups (total; Cobb angle: 19.4°±10.6°, C7SVA: 5.3±2.9 cm, PI-LL: 12.1°±5.1°). Gait pattern, stride, and velocity all improved significantly after surgery (total; velocity: 62.3±8.9m/min, stride: 106.8±12.3 cm, p=.01). The knee angle at the heel contact phase and hip range of motion (ROM) were also significantly improved at postoperation (total; hip ROM: preoperation: 29.2°±9.1°, postoperation: 36.2°±4.8°, knee angle; preoperation: 10.6°±6.6°, postoperation: 4.4°±2.8°). No difference was observed for the pelvis and shoulder rotation on the horizontal plane at postoperation in both groups (total; pelvis rotation; preoperation: 7.4°±3.4°, postoperation: 7.9°±2.4°, shoulder rotation; preoperation: 7.4°±2.9°, postoperation: 8.7°±3.6°). The head vertical deviation was also not changed postoperatively in both groups (preoperation: 3.1±0.9 cm, postoperation: 3.1±0.8 cm).

CONCLUSIONS

Both UT and LT groups achieved similar improvement of gait ability and pattern after surgery. Additional studies will be needed to further define the effect of UIV for the activity of daily living such as fast walking, stepping the stairs, or standing from the chair in ASDs.

Adults With Idiopathic Scoliosis Diagnosed at Youth Experience Similar Physical Activity and Fracture Rate as Controls

STUDY DESIGN

Cross-sectional.

OBJECTIVE

To describe physical activity level and fracture rates in adults with idiopathic scoliosis, diagnosed before maturity, and to compare with a control group.

SUMMARY OF BACKGROUND DATA

A previous study found a lower level of sporting activities in adults treated for idiopathic scoliosis compared with controls. Other studies have shown a lower bone mass in adults with idiopathic scoliosis compared with controls.

METHODS

One thousand two hundred seventy-eight adults (aged 18-71 yr) with idiopathic scoliosis and 214 controls (aged 18-70 yr) were included and answered the International Physical Activity Questionnaire - Short Form (IPAQ-SF) and questions about previous fractures. The three scoliosis treatment groups (untreated n = 360, brace n = 460, and surgically treated n = 458) were compared. Furthermore, a comparison based on onset (juvenile n = 169 or adolescent n = 976) was performed. Achieved weekly moderate activity level and metabolic equivalent task (MET) minutes/week were assessed for patients and controls. Statistical comparisons were made with analysis of covariance with adjustments for age, body mass index, and sex.

RESULTS

The proportion achieving weekly moderate activity level was 962 out of 1278 for individuals with idiopathic scoliosis (75%) and 157 out of 214 (73%) for controls (P = 0.40). The scoliosis patients reported 2016 MET-minutes/week (median value) and the controls 2456 (P = 0.06). Fracture rates did not differ (P = 0.72). Fewer surgically treated individuals achieved moderate activity level (P = 0.046) compared with the untreated and the previously braced individuals. No difference was seen regarding MET-minutes/week (P = 0.86). No differences were seen between individuals with a juvenile onset compared with individuals with an adolescent onset (all P ≥ 0.05).

CONCLUSION

Adults with idiopathic scoliosis have similar physical activity level and do not sustain more fractures compared with controls. Adults with surgically treated idiopathic scoliosis have slightly lower physical activity level than previously braced and untreated patients. Onset of idiopathic scoliosis does not affect physical activity level.

LEVEL OF EVIDENCE

2.

Walking balance and compensatory gait mechanisms in surgically treated patients with adult spinal deformity

BACKGROUND CONTEXT

Gait patterns and their relationship to demographic and radiographic data in patients with adult spinal deformity (ASD) have not been fully documented.

PURPOSE

This study aimed to assess gait pattern in patients with ASD and the effect of corrective spinal surgery on gait.

DESIGN/SETTING

This is a prospective case series.

PATIENT SAMPLE

The gait patterns of 33 consecutive women with ASD (age 67.1 years; body mass index [BMI] 22.5±2.5 kg/m², Cobb angle 46.8±18.2°, coronal vertical axis [CVA] 1.5±3.7 cm, C7 sagittal vertical axis [SVA] 9.1±6.4 cm, pelvic incidence minus lumbar lordosis [PI-LL] 38.2±22.1°, and lean volume of the lower leg, 5.5±0.6 kg) before and after corrective surgery were compared with those of 33 age- and gender-matched healthy volunteers.

OUTCOME MEASURES

Scoliosis Research Society Patient Questionnaire (SRS22r), Oswestry Disability Index (ODI), and forceplate analysis.

METHODS

All subjects underwent gait analysis on a custom-built forceplate using optical markers placed on all joints and spinal processes. Dual X-ray absorptiometry scores were used to calculate the lean composition of the lower legs. Subjects with ASD were followed for at least 2 years post operation.

RESULTS

Preop mean values showed that patients with ASD had a significantly worse gait velocity (54±10 m/min vs. 70.7±12.9 m/min, p<.01) and stride (97.8±13.4 cm vs. 115.3±15.1 cm, p<.01), but no difference was observed in the stance-to-swing ratio. The right and left ground reaction force vectors were also discordant in the ASD group (vertical direction; r=0.84 vs. r=.97, p=.01). The hip range of motion (ROM) was also significantly decreased in ASD. Correlation coefficient showed moderate correlations between the preoperative gait velocity and the gravity line (GL), PI, ROM of the lower extremity joints, and lean volume, and between the stride and the lean volume, GL, and PI-LL. Gait pattern, stride, and velocity all improved significantly in the patients with ASD after surgery, but were still not as good as in healthy volunteers. The SRS22r satisfaction domain correlated moderately with postoperative gait velocity (r=0.34).

CONCLUSIONS

The patients with ASD had an asymmetric gait pattern and impaired gait ability compared with healthy volunteers. Gait ability correlated significantly with the GL, spinopelvic alignment, lower extremity joint ROM, and lean volume. The surgical correction of spinopelvic alignment and exercises to build muscle strength may improve the gait pattern and ability in patients with ASD.

Effect of corrective long spinal fusion to the ilium on physical function in patients with adult spinal deformity

PURPOSE

To identify the effects of corrective long spinal fusion to the ilium on physical function in patients with adult spinal deformity (ASD).

METHODS

Thirty patients who underwent corrective long spinal fusion to the ilium were prospectively analysed. Patients were divided into the ++ group [sagittal vertical axis (SVA) ≥ 95 mm and pelvic tilt (PT) ≥ 30°, 14 patients] and 0+ group (SVA <95 mm or PT <30°, 16 patients). Subjects' low back pain [visual analogue scale (VAS) (pain with motion)], muscle strength (knee extensors and hip flexors), balance [timed up and go (TUG)], gait performance [10-metre walking test (10MWT, maximum speed), and 6-minute walk test (6MWT)] were assessed before surgery, at discharge, and 6 and 12 months after the surgery.

RESULTS

All study patients had a significant improvement in the VAS score between baseline and at discharge, 6 months postoperatively, and 12 months postoperatively. The values of the TUG and 6MWT significantly improved 12 months postoperatively. The values of the TUG, 10MWT, and 6MWT improved significantly more in the ++ group than in the 0+ group at 12 months.

CONCLUSION

Corrective long spinal fusion contributed to improving back pain at discharge and gait ability at 12 months in patients with ASD.

Multisegment Kinematics of the Spinal Column: Soft Tissue Artifacts Assessment

A major challenge in the assessment of intersegmental spinal column angles during trunk motion is the inherent error in recording the movement of bony anatomical landmarks caused by soft tissue artifacts (STAs). This study aims to perform an uncertainty analysis and estimate the typical errors induced by STA into the intersegmental angles of a multisegment spinal column model during trunk bending in different directions by modeling the relative displacement between skin-mounted markers and actual bony landmarks during trunk bending. First, we modeled the maximum displacement of markers relative to the bony landmarks with a multivariate Gaussian distribution. In order to estimate the distribution parameters, we measured these relative displacements on five subjects at maximum trunk bending posture. Then, in order to model the error depending on trunk bending angle, we assumed that the error grows linearly as a function of the bending angle. Second, we applied our error model to the trunk motion measurement of 11 subjects to estimate the corrected trajectories of the bony landmarks and investigate the errors induced into the intersegmental angles of a multisegment spinal column model. For this purpose, the trunk was modeled as a seven-segment rigid-body system described using 23 reflective markers placed on various bony landmarks of the spinal column. Eleven seated subjects performed trunk bending in five directions and the three-dimensional (3D) intersegmental angles during trunk bending were calculated before and after error correction. While STA minimally affected the intersegmental angles in the sagittal plane (<16%), it considerably corrupted the intersegmental angles in the coronal (error ranged from 59% to 551%) and transverse (up to 161%) planes. Therefore, we recommend using the proposed error suppression technique for STA-induced error compensation as a tool to achieve more accurate spinal column kinematics measurements. Particularly, for intersegmental rotations in the coronal and transverse planes that have small range and are highly sensitive to measurement errors, the proposed technique makes the measurement more appropriate for use in clinical decision-making processes.

Influence of side-shift therapy associated or not with a shoe lift on idiopathic scoliosis

Abstract Introduction: The benefits of side-shift therapy associated with a shoe lift in scoliosis can act by reorganizing the asymmetries found in these individuals. The aim of this study was to analyze the influence of side-shift therapy with or without a high or low shoe lift in patients with idiopathic scoliosis. Materials and Methods: 10 individuals of both genders, aged 13-24 years, were selected, with scoliosis "S" and right thoracic and left lumbar greater than 10º. Initially the order of the task was static and then dynamic, after which there was a draw for the conditions with the shoe lift. The values of postural angles during the five lateral tilt movements were obtained and also the minimum and maximum values of each movement. The average value of postural angle in the static position, without a shoe lift, was used as a reference. Results: The movement associated with the shoe lift demonstrated less significant results compared with the effect of the static shoe lift and the side-shift movements performed in isolation, no significant results in any angle were found. Discussion: Both movements, to the side of the convexity or to the opposite side, seemed to decrease the effect of the shoe lift. The side-shift movement performed in isolation failed to influence the postural angles in general, demonstrating that acute intervention may not be efficient. Conclusion: The influence of side-shift therapy associated with a high or low shoe lift on both sides was effective, but the shoe lift in the static position produced the most significant changes and therefore is considered a better intervention in order to prevent the progression of double curve in patients with idiopathic scoliosis.

Gait behaviors as an objective surgical outcome in low back disorders: A systematic review

BACKGROUND

Objective motor performance measures, especially gait assessment, could improve evaluation of low back disorder surgeries. However, no study has compared the relative effectiveness of gait parameters for assessing motor performance in low back disorders after surgery. The purpose of the current review was to determine the sensitive gait parameters that address physical improvements in each specific spinal disorder after surgical intervention.

METHODS

Articles were searched with the following inclusion criteria: 1) population studied consisted of individuals with low back disorders requiring surgery; 2) low back disorder was measured objectively using gait assessment tests pre- and post-surgery. The quality of the selected studies was assessed using Delphi consensus, and meta-analysis was performed to compare pre- and post-surgical changes.

FINDINGS

Thirteen articles met inclusion criteria, which, almost exclusively, addressed two types of spinal disorders/interventions: 1) scoliosis/spinal fusion; and 2) stenosis/decompression. For patients with scoliosis, improvements in hip and shoulder motion (effect size=0.32-1.58), energy expenditure (effect size=0.59-1.18), and activity symmetry of upper-body muscles during gait were present after spinal fusion. For patients with spinal stenosis, increases in gait speed, stride length, cadence, symmetry, walking smoothness, and walking endurance (effect size=0.60-2.50), and decrease in gait variability (effect size=1.45) were observed after decompression surgery.

INTERPRETATION

For patients with scoliosis, gait improvements can be better assessed by measuring upper-body motion and EMG rather than the lower extremities. For patients with spinal stenosis, motor performance improvements can be captured by measuring walking spatio-temporal parameters, gait patterns, and walking endurance.

Has a Mono- or Bisegmental Lumbar Spinal Fusion Surgery an Influence on Self-Assessed Quality of Life, Trunk Range of Motion, and Gait Performance?

STUDY DESIGN

This investigation prospectively compared self-assessed quality of life and biomechanical measures of physical function before and after spinal fusion surgery in 26 adult patients with symptomatic lumbar degenerative disease.

OBJECTIVE

The objective was to demonstrate that (1) due to a reduction of low back pain, quality of life as well as gait parameters would improve after a spinal fusion surgery and (2) gait performance is more similar to that observed in healthy controls at the same age, whereas trunk range of motion remains unchanged after surgery.

SUMMARY OF BACKGROUND DATA

Current outcome evaluations of spinal fusion surgery are based on radiological changes and self-report questionnaires. However, these traditional measures do not sufficiently assess the functionality.

METHODS

Twenty-six patients with a mean age of 59.3 (SD: 10.1) years and 20 healthy subjects at the same age were evaluated. Before and approximately 6 months after a mono- or bisegmental spinal fusion surgery, patients completed self-report questionnaires and biomechanical assessments of gait analysis and trunk range of motion in the 3 principal planes of the body.

RESULTS

Results indicated an improvement in quality of life as well as an increased pain-free walking distance, walking speed, step length, and maximum hip extension during the stance phase of gait. Anterior pelvis and thorax tilt were significantly reduced after the surgery without significant differences compared with the control group. Regarding the trunk range of motion, we observed a decrease in maximum forward flexion and an increase in the fingertip-floor distance after surgery.

CONCLUSION

The study results show that lumbar spinal fusion is a useful procedure to improve patient's quality of life and gait performance. Although we performed only mono- and 2-level fusions, the sagittal alignment of the pelvis and thorax during walking was normalized. Clinical gait analysis contributes to the advancement of our knowledge regarding the functional changes after a spinal fusion surgery.

LEVEL OF EVIDENCE

2.

Examination of a lumbar spine biomechanical model for assessing axial compression, shear, and bending moment using selected Olympic lifts

BACKGROUND/AIMS

Loading during concurrent bending and compression associated with deadlift, hang clean and hang snatch lifts carries the potential for injury to the intervertebral discs, muscles and ligaments. This study examined the capacity of a newly developed spinal model to compute shear and compressive forces, and bending moments in lumbar spine for each lift.

METHODS

Five male subjects participated in the study. The spine was modeled as a chain of rigid bodies (vertebrae) connected via the intervertebral discs. Each vertebral reference frame was centered in the center of mass of the vertebral body, and its principal directions were axial, anterior-posterior, and medial-lateral.

RESULTS

The results demonstrated the capacity of this spinal model to assess forces and bending moments at and about the lumbar vertebrae by showing the variations among these variables with different lifting techniques.

CONCLUSION

These results show the model's potential as a diagnostic tool.

Dynamic balance assessment during gait in spinal pathologies - a literature review

The role of the spine as a gait stabilizer is essential. Dynamic assessment, while walking, might provide complementary data to improve spinal deformity management. The aim of this paper was to review spine dynamic behavior and the various methods that have been used to assess gait dynamic balance in order to explore the consequences of spinal deformities while walking. A review was performed by obtaining publications from five electronic databases. All papers reporting pathological or non-pathological spine dynamic behavior during gait and dynamic balance assessment methods were included. Sixty articles were selected. Results varied widely according to pathologies, study conditions, and balance assessment techniques. Three methods assessing dynamic stability during gait were identified: local-orbital dynamic stability, tri-axial accelerometry, and dynamic stability margin. Data from conventional gait analysis techniques were established essentially for scoliosis and low back pain, but they do not assess specific consequences on gait dynamic balance. Three techniques investigate gait dynamic balance and have been validated in normal subjects. Further investigations need to be performed for validation in spinal pathologies as well as the value for clinical practice.

LEVEL OF EVIDENCE

Level IV.

Feasibility of a cost-effective, video analysis software-based mobility protocol for objective spine kinematics and gait metrics: a proof of concept study

The purpose of this study was to investigate the potential of a high-throughput, easily implemented, cost-effective, video analysis software-based mobility protocol to quantify spine kinematics. This prospective cohort study of clinical biomechanics implemented 2-dimensional (2D) image processing at a tertiary-care academic institution. Ten healthy, able-bodied volunteers were recruited for 2D videography of gait and functional motion. The reliability of a 2D video analysis software program for gait and range of motion metrics was evaluated over 2 independent experimental sessions, assessing for inter-trial, inter-session, and inter-rater reliability. Healthy volunteers were evaluated for simple forward and side bending, rotation, treadmill stride length, and more complex seated-to-standing tasks. Based on established intraclass correlation coefficients, results indicated that reliability was considered good to excellent for simple forward and side bending, rotation, stride length, and more complex sit-to-standing tasks. In conclusion, a cost-effective, 2D, video analysis software-based mobility protocol represents a feasible and clinically useful approach for objective spine kinematics and gait metrics. As the complication rate of operative management in the setting of spinal deformity is weighed against functional performance and quality of life measures, an objective analysis tool in combination with an appropriate protocol will aid in clinical assessments and lead to an increased evidence base for management options and decision algorithms.

Gait stability improvement after fusion surgery for adolescent idiopathic scoliosis is influenced by corrective measures in coronal and sagittal planes

To achieve optimal results after fusion for adolescent idiopathic scoliosis (AIS), radiographic parameters must be aligned with motion and performance. The effects of fusion on balance are poorly understood. Center of mass (COM) excursion and instantaneous interaction with center of pressure (COP) provides information about patients' balancing ability during gait. This study investigates the interaction between COM and COP (COM-COP) in AIS patients before and one year after spine fusion and determines what radiographic goals predict restoration of harmonious COM-COP. This was a prospective study that investigated sixteen adolescents with AIS curvature >30˚ requiring surgical correction. Clinical outcomes measures, X-rays, and 3D motion-capture gait analysis were collected. Sagittal and coronal COM and COP offsets and inclination angles were calculated from positional data. COM excursion was calculated as peak COM displacement based on mediolateral and vertical deviation from a line fitted to the patient's path. Radiographic parameters were measured to determine variables predictive of change in COM excursion. Post-operatively, average COM peak displacement decreased (42.6 to 13.1 mm, p=0.001) and COM peak vertical displacement remained unchanged (17.0 to 16.3 mm, p=0.472). COM-COP inclination angles reduced in the coronal, but not sagittal plane. Coronal lower extremity peak inclination angles reduced (8.8˚ to 7.5˚, p=0.025), correlating with C7 plumb-line offset (R=0.581, p=0.018). Thoracic Cobb, thoracic kyphosis, and C7 plumb-line were predictors of change in COM excursion. Mediolateral COM excursion post-surgery may reflect an attempt to reduce kinetic demands with improved spinal alignment. Although AIS correction has historically focused on the coronal plane, sagittal parameters may be more important for motion than previously theorized.

Loss in spinal motion from inclusion of a single midlumbar level in posterior spinal fusion for adolescent idiopathic scoliosis

STUDY DESIGN

Prospective study.

OBJECTIVE

Evaluate the impact of the distal fusion level on overall spine motion in patients with adolescent idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

In the surgical treatment of adolescent idiopathic scoliosis, the impact of incorporating a single additional distal lumbar fusion level on residual spinal motion is unclear. This study uses radiographs and computerized motion capture technology to determine whether the addition of a single lumbar level in a posterior fusion construct produces a detectable alteration in spinal motion.

METHODS

Twenty-three patients with adolescent idiopathic scoliosis were evaluated with standing radiographs and computerized motion analysis preoperatively and 1 year after fusion. Patients were divided into 2 groups: L1-L2 group (distal fusion ended at L1-L2) and an L3 group (distal fusion ended at L3). Cobb angle, coronal vertical alignment, sagittal vertical alignment, thoracic kyphosis, and lumbar lordosis were measured from radiographs. Three-dimensional motion data were obtained for static standing and repeated bending or twisting motions. Statistical analysis was performed with Student t test, analysis of variance, and Fisher exact methods.

RESULTS

Both the L1-L2 and L3 groups demonstrated loss of spinal motion compared with preoperative values. The L1-L2 group showed a significant loss of rotational motion but no significant loss of motion in the sagittal and coronal planes. The L3 group demonstrated significant loss of motion in both the coronal plane and the rotational plane. When the 2 groups were compared, the L3 group showed a significant loss of coronal plane bending (18° ± 10°, P = 0.002).

CONCLUSION

Distal extension of a posterior spinal fusion construct to include L3 results in a significant decrease in spine motion in at least one plane. Preservation of a single lumbar segment may improve overall spine motion in the short term and may have implications for the long-term health of the unfused spine.

LEVEL OF EVIDENCE

3.

Crouch gait in persons with positive sagittal spine alignment resolves with surgery

OBJECTIVE

Degenerative spinal conditions often result in positive sagittal alignment which may be corrected using multi-segment spinal reconstructive surgeries. The purpose of this study was to investigate gait kinematics before and after spinal reconstructive surgery in persons with positive sagittal alignment.

METHODS

Subjects presenting with positive sagittal alignment of greater than or equal to 7 cm who were treated with spinal reconstructive surgery were included in this study. Gait analyses were conducted pre- and 6 months post-operatively. Data were collected while subjects stood quietly for 20s and walked at their normal self-selected walking speed.

RESULTS

For 12 subjects, sagittal spine alignment during standing and walking was significantly decreased post-operatively (p<0.0001 for standing and p<0.0005 for walking). Prior to surgery, the subjects appeared to adopt a crouch gait with the knee flexion angle at mid terminal stance decreasing significantly after surgery (p<0.0 for the dominant lower limb and p<0.0 for the non-dominant lower limb). Additionally, dominant step length (p<0.003) and non-dominant step length (p<0.001) increased significantly after surgery.

CONCLUSIONS

Positive sagittal alignment resulted in crouch gait, which was resolved after multi-segment reconstructive spinal surgery that improved sagittal spinal alignment. Step and stride lengths also improved after surgical correction of the sagittal alignment.

The risk of stroke after spinal fusion surgery: a national cohort study

BACKGROUND CONTEXT

Postoperative stroke is a rare complication of spinal fusion surgery, but its relevant risk and incidence remain unclear.

PURPOSE

To investigate the incidence and risk of stroke after spinal fusion surgery.

STUDY DESIGN

Cohort study.

PATIENT SAMPLE

All study subjects were extracted from a nationwide representative cohort of one million people from 2000 to 2005.

OUTCOME MEASURES

Stroke, including hemorrhagic and ischemic, during the study period.

METHODS

An exposure group of 2,249 subjects who received spinal fusion surgery during the study period was compared with 2,203 control subjects matched by age, sex, and propensity score. All were followed up for 3 years for all kinds of stroke. Demographics, comorbidities, and nonmeasurable covariates were matched between the two groups. Kaplan-Meier analyses were performed, with adjustments by Cox regression model.

RESULTS

There were 4,452 subjects, including 2,249 spinal fusion patients and 2,203 controls, who were followed up for 12,967 person-years. The incidence rates of any, hemorrhagic, and ischemic strokes were 9.95, 1.21, and 8.86, respectively, per 1,000 person-years in the spinal fusion group and 11.5, 1.69, and 9.93, respectively, in the comparison group. Patients who received spinal fusion surgery were less likely to have any stroke (crude hazard ratio [HR]=0.87, p=.393), hemorrhagic stroke (HR=0.72, p=.473), and ischemic stroke (HR=0.89, p=.582) than the comparison group but without statistical significance. After adjusting for demographics, comorbidities, and medications, there were still no significant differences for risks of any, hemorrhagic, and ischemic strokes (adjusted HR=0.89, 1.36, and 0.87; p=.522, .553, and .477, respectively) in the spinal fusion group.

CONCLUSIONS

Patients receiving spinal fusion surgery have similar incidence rates of having a stroke within 3 years postoperation as those without surgery. Risks of any postoperative stroke are similar or insignificantly lower in the spinal fusion group.

Short or long fusion after thoracolumbar burst fractures does not alter selected gait parameters: a preliminary study

We evaluated the gait characteristics of patients who had short or long-segment fusion after thoracolumbar burst fractures. The study included 12 patients (5 male, 7 female) who had vertebral fusion after traumatic thoracolumbar region (T12-L2) burst fractures. Patients were divided into two groups based on fixation type (short or long segment). Twelve healthy age and sex-matched subjects (seven male, five female) served as controls. Quantitative gait data, including all time-distance (walking velocity, cadence, step time, step length, double support time), kinematic (joint rotation angles of pelvis, hip, knee, and ankle), and kinetic data (moments of hip in sagittal and coronal plane) were collected. Three patients had a T12, six patients an L1, and three patients had an L2 lesion. Patients in the two groups were similar in terms of age, sex, and time since operation. No significant differences were found in the time-distance, kinematic, and kinetic gait characteristics between the two groups. This preliminary study reveals that the gait characteristics of patients with short and long-segment fusion after thoracolumbar burst fractures were similar to those of healthy subjects and did not differ from each other. However, the present results should be interpreted with caution due to the small sample size. Future studies with larger groups are needed to provide additional data to validate these findings.

The morbidity of an anterior thoracolumbar approach: adult spinal deformity patients with greater than five-year follow-up

STUDY DESIGN

Retrospective study.

OBJECTIVE

To analyze the complications and patient satisfaction related to an anterior thoracolumbar approach in the treatment of adult spinal deformity.

SUMMARY OF BACKGROUND DATA

There is no long-term follow-up data on the effects of an anterior thoracolumbar approach on adult spinal deformity patients.

METHODS

A specific questionnaire was used to evaluate long-term follow-up (average, 10.3 years; range, 5-20.6) of 62 adult patients who underwent spinal deformity surgery performed through an anterior thoracolumbar approach. Twenty-six patients had over 10 years follow-up and 36 were between 5 and 10 years follow-up. The questionnaire was composed of detailed scar-related subquestions for pain, appearance, bulging, daily life, and patient's personal opinion of surgery. Postoperative Oswestry Disability Index (scores) were also obtained.

RESULTS

The average age and number of anterior fusion levels were 47.9 (range, 20-74) and 5.6 (range, 2-12), respectively. Although 82.2% patients were satisfied with the results of their surgery, in general, many of the patients were dissatisfied with aspects related to their anterior incision. For the pain domain, 20 patients (32.3%, 6 with >10 years follow-up, 14 patients with 5 years follow-up) had pain over their thoracolumbar scar, which they rated as moderate to severe. Twenty-seven patients (43.5%) had bulging of their scar region, 4 were surgically indicated for repair, and 1 had multiple surgical repairs. Twelve patients (19.4%) felt they had a poor outcome related to the postoperative appearance of their anterior wound. Fifteen patients (24.2%) showed limitations in activities of daily living due to their anterior incision. Three patients with >10 years of follow-up and 4 with >5 years of follow-up felt they were getting worse. The average Oswestry Disability Index score was 25.0 +/- 16.3 (range, 0-52) postoperative.

CONCLUSION

This is the first long-term (minimum 5 years) follow-up study focusing on patient outcomes after an anterior thoracolumbar approach for adult spinal deformity treatment. This approach appears to be associated with an appreciable high rate of postoperative pain (32.3%), bulging (43.5%), and functional disturbance (24.2%). Therefore, surgeons should use caution when recommending this approach to future adult spinal deformity patients.

Effect of trunk inclination on lower limb joint and lumbar moments in able men during the stance phase of gait

BACKGROUND

Though the effect of imposed trunk posture affects walking patterns little is known about the effect of natural orientation of the trunk on gait. The objectives of this study are to test if the lower limb joint and thoraco-lumbar moments are similar in subjects who maintain an average natural forward or backward trunk inclination during gait and verify if the lower limbs are equally affected.

METHODS

Twenty-five young men were divided according to their natural backward or forward trunk inclination during level walking. Ankle, knee, hip and thoraco-lumbar moments were calculated by an inverse dynamic approach for the two limbs. A two-way ANOVA was performed on peak lower limb moments. A one-way ANOVA was performed on thoraco-lumbar peak moments.

FINDINGS

There was a main effect for both trunk inclinations and lower limb sides but no interaction. For the forward leaners, the duration of hip extension moment was longer (P<0.001) while the hip flexion moment was 1.3 times smaller (P<0.001). Differences between the lower limb sides were noted in all joints but at push-off of the stance phase only. The two thoraco-lumbar extension moments were, respectively, 1.4 times higher for the forward leaners while the two flexion moments were approximately 1.4 times higher for the backward leaners.

INTERPRETATIONS

The backward leaners propel themselves with a strong hip flexor activity at push-off while the forward leaners use their hip muscles throughout stance. These results support the idea that trunk inclinations and moment variations are associated with the type of walking patterns.

Rate of complications in scoliosis surgery - a systematic review of the Pub Med literature

Background

Spinal fusion surgery is currently recommended when curve magnitude exceeds 40–45 degrees. Early attempts at spinal fusion surgery which were aimed to leave the patients with a mild residual deformity, failed to meet such expectations. These aims have since been revised to the more modest goals of preventing progression, restoring 'acceptability' of the clinical deformity and reducing curvature.

In view of the fact that there is no evidence that health related signs and symptoms of scoliosis can be altered by spinal fusion in the long-term, a clear medical indication for this treatment cannot be derived. Knowledge concerning the rate of complications of scoliosis surgery may enable us to establish a cost/benefit relation of this intervention and to improve the standard of the information and advice given to patients. It is also hoped that this study will help to answer questions in relation to the limiting choice between the risks of surgery and the "wait and see – observation only until surgery might be recommended", strategy widely used. The purpose of this review is to present the actual data available on the rate of complications in scoliosis surgery.

Materials and methods

Search strategy for identification of studies; Pub Med and the SOSORT scoliosis library, limited to English language and bibliographies of all reviewed articles. The search strategy included the terms; 'scoliosis'; 'rate of complications'; 'spine surgery'; 'scoliosis surgery'; 'spondylodesis'; 'spinal instrumentation' and 'spine fusion'.

Results

The electronic search carried out on the 1^st February 2008 with the key words "scoliosis", "surgery", "complications" revealed 2590 titles, which not necessarily attributed to our quest for the term "rate of complications". 287 titles were found when the term "rate of complications" was used as a key word. Rates of complication varied between 0 and 89% depending on the aetiology of the entity investigated. Long-term rates of complications have not yet been reported upon.

Conclusion

Scoliosis surgery has a varying but high rate of complications. A medical indication for this treatment cannot be established in view of the lack of evidence. The rate of complications may even be higher than reported. Long-term risks of scoliosis surgery have not yet been reported upon in research. Mandatory reporting for all spinal implants in a standardized way using a spreadsheet list of all recognised complications to reveal a 2-year, 5-year, 10-year and 20-year rate of complications should be established. Trials with untreated control groups in the field of scoliosis raise ethical issues, as the control group could be exposed to the risks of undergoing such surgery.

The effect of trunk flexion on able-bodied gait

This study examined the effect of sagittal trunk posture on the gait of able-bodied subjects. Understanding the effect of trunk posture on gait is of clinical interest since alterations in trunk posture often occur with age or in the presence of spinal pathologies, such as lumbar flatback. Gait analysis was conducted on 14 adults walking at self-selected slow, normal, and fast walking speeds while maintaining three trunk postures: upright, and with 25+/-7 degrees and 50+/-7 degrees of trunk flexion from the vertical. During trunk-flexed gait, subjects adopted a crouch posture characterized by sustained knee flexion during stance and an increase in ankle dorsiflexion and hip flexion angles. During stance, these kinematic adaptations produced a posterior shift in the positions of the trunk and pelvis, which helped to offset the anterior shift in the trunk mass that occurred with trunk flexion. In this way, kinematic adaptations may have been used to maintain balance by shifting the body's center of mass to a position similar to that of upright walking. These changes in lower limb joint kinematics created a phase lag in the position of the hip joint center relative to that of the ankle joint center in the sagittal plane. Alterations in the sagittal alignment of the hip and ankle joint positions were associated with a phase lag in the vertical position, velocity, and acceleration of the body's center of mass (BCOM) relative to upright walking. Since the vertical ground reaction force (GRF(v)) is proportional to the vertical acceleration of the BCOM, significant changes were also seen in the GRF(v) during trunk-flexed gait. In summary, kinematic adaptations necessary to maintain dynamic balance altered the trajectory and acceleration of the BCOM in the vertical direction, which was reflected in the GRF(v). The results of this study may help clinicians better understand the nature and impact of compensatory mechanisms in patients who exhibit trunk-flexed postures during gait.

Inter-trial and test-retest reliability of kinematic and kinetic gait parameters among subjects with adolescent idiopathic scoliosis

Gait analysis is actually used in subjects with scoliosis to determine the change in lower limb parameters after surgery, but the reliability of these parameters still remained unknown. The purpose of this study was to assess the repeatability of traditional gait parameters in subjects with adolescent idiopathic scoliosis (AIS) and to estimate the associated standard error of measurement (SEM). A test-retest design was used to assess the reliability of gait parameters at self-selected and fast speeds. A convenience sample of 20 girls aged from 12 to 17 years, with an idiopathic scoliosis (King classification: types I, II or III; Cobb angle 17-50 degrees) participated in the study. Five good trials were recorded on two occasions. The time-distance, kinematic, and kinetic gait parameters were recorded using foot-switches in combination with a three-dimensional motion analysis system (Optotrak) and Advanced Mechanical Technologies Inc., (AMTI) Watertown, MA, USA; force plates. The coefficients of dependability and SEM derived from the generalizability theory were used to assess the reliability. Inter-trial reliability was good for time-distance, kinematic, and kinetic (absolute and normalized) gait parameters except for the medio-lateral ground reaction force (GRF) component and the ankle dorsiflexor moment (phi = 0.60-0.77). Test-retest reliability was higher for the kinetic than for the kinematic parameters. These coefficients ranged from 0.42 to 0.58 for the time-distance parameters; from 0.55 to 0.88 for the angular displacements and from 0.25 to 0.99 for the kinetic parameters. The SEMs were lower than 3.3 degrees for the angular displacements and lower than 8 Nm (0.15 Nm/kg) and 36 W (0.54 W/Kg) for the joint moments and powers regardless of the speed. Several gait parameters are reliable among subjects with AIS and can be used to assess the evolution of the spinal modifications and the impact of treatment on their lower limb gait pattern.

Impact of spine surgery on signs and symptoms of spinal deformity

Paediatric scoliosis is associated with signs and symptoms including reduced pulmonary function, increased pain and impaired quality of life, all of which worsen during adulthood, even when the curvature remains stable. Spinal fusion has been used as a treatment for nearly 100 years. In 1941, the American Orthopedic Association reported that for 70% of patients treated surgically, outcome was fair or poor: an average 65% curvature correction was reduced to 27% at >2 year follow-up and the torso deformity was unchanged or worse. Outcome was worse in children treated surgically before age 10, despite earlier intervention. Today, a reduced magnitude of curvature obtained by spinal fusion in adolescence can be maintained for decades. However, successful surgery still does not eliminate spinal curvature and it introduces irreversible complications whose long-term impact is poorly understood. For most patients there is little or no improvement in pulmonary function. Some report improved pain after surgery, some report no improvement and some report increased pain. The rib deformity is eliminated only by rib resection which can dramatically reduce respiratory function even in healthy adolescents. Outcome for pulmonary function and deformity is worse in patients treated surgically before the age of 10 years, despite earlier intervention. Research to develop effective non-surgical methods to prevent progression of mild, reversible spinal curvatures into complex, irreversible structural deformities, is long overdue.

A kinematic model to assess spinal motion during walking

STUDY DESIGN AND OBJECTIVES

A 3-dimensional multi-segment kinematic spine model was developed for noninvasive analysis of spinal motion during walking. Preliminary data from able-bodied ambulators were collected and analyzed using the model.

SUMMARY OF BACKGROUND DATA

Neither the spine's role during walking nor the effect of surgical spinal stabilization on gait is fully understood. Typically, gait analysis models disregard the spine entirely or regard it as a single rigid structure. Data on regional spinal movements, in conjunction with lower limb data, associated with walking are scarce.

METHODS

KinTrak software (Motion Analysis Corp., Santa Rosa, CA) was used to create a biomechanical model for analysis of 3-dimensional regional spinal movements. Measuring known angles from a mechanical model and comparing them to the calculated angles validated the kinematic model. Spine motion data were collected from 10 able-bodied adults walking at 5 self-selected speeds. These results were compared to data reported in the literature.

RESULTS

The uniaxial angles measured on the mechanical model were within 5 degrees of the calculated kinematic model angles, and the coupled angles were within 2 degrees. Regional spine kinematics from able-bodied subjects calculated with this model compared well to data reported by other authors.

CONCLUSIONS

A multi-segment kinematic spine model has been developed and validated for analysis of spinal motion during walking. By understanding the spine's role during ambulation and the cause-and-effect relationship between spine motion and lower limb motion, preoperative planning may be augmented to restore normal alignment and balance with minimal negative effects on walking.

Effect of selective dorsal rhizotomy in the treatment of children with cerebral palsy

OBJECT

In this investigation the authors compared impairment and functional outcomes between two groups of children with cerebral palsy (CP): one group underwent selective dorsal rhizotomy (SDR) followed by intensive physical therapy (PT), and the other group underwent the latter only (PT group). Data from an age-matched group of children without disability (nondisabled [ND] group) were also collected.

METHODS

Data pertaining to the 68 children with CP were collected before any intervention and again 8 and 20 months afterwards. Data regarding the 40 children in the ND group were collected in a single session.

CONCLUSIONS

Although patients in both groups with CP were weaker than those in the ND group, they did have strength gains. Gait speed in the SDR-PT group was slower than that in the ND group preoperatively but not at 20 months postoperatively. Gait speed in the PT group remained slower than that in the ND group. The pre- to postoperative change in the Gross Motor Abilities Estimate score was significantly greater in the SDR-PT group than in the PT-only group. An effective treatment for children with CP, SDR offers gains in strength, gait speed, and overall gross motor function.

The impact of positive sagittal balance in adult spinal deformity

STUDY DESIGN

This study is a retrospective review of 752 patients with adult spinal deformity enrolled in a multicenter prospective database in 2002 and 2003. Patients with positive sagittal balance (N = 352) were further evaluated regarding radiographic parameters and health status measures, including the Scoliosis Research Society patient questionnaire, MOS short form-12, and Oswestry Disability Index.

OBJECTIVES

To examine patients with adult deformity with positive sagittal balance to define parameters within that group that might differentially predict clinical impact.

SUMMARY OF BACKGROUND DATA

In a multicenter study of 298 adults with spinal deformity, positive sagittal balance was identified as the radiographic parameter most highly correlated with adverse health status outcomes.

METHODS

Radiographic evaluation was performed according to a standardized protocol for 36-inch standing radiographs. Magnitude of positive sagittal balance and regional sagittal Cobb angle measures were recorded. Statistical correlation between radiographic parameters and health status measures were performed. Potentially confounding variables were assessed.

RESULTS

Positive sagittal balance was identified in 352 patients. The C7 plumb line deviation ranged from 1 to 271 mm. All measures of health status showed significantly poorer scores as C7 plumb line deviation increased. Patients with relative kyphosis in the lumbar region had significantly more disability than patients with normal or lordotic lumbar sagittal Cobb measures.

CONCLUSIONS

This study shows that although even mildly positive sagittal balance is somewhat detrimental, severity of symptoms increases in a linear fashion with progressive sagittal imbalance. The results also show that kyphosis is more favorable in the upper thoracic region but very poorly tolerated in the lumbar spine.

Methods to locate center of gravity in scoliosis

STUDY DESIGN

Prospective evaluation of the location of the center of gravity during supine, standing, and gait.

OBJECTIVE

Develop methods to quantify center of gravity locations in patients with scoliosis and controls and to evaluate the merit of the quantitative assumptions relative to spinal fusion surgery.

SUMMARY AND BACKGROUND DATA

The center of gravity, or balance point of the body, is generally considered to be the single best estimate of the body's location. To date, investigators have not examined the body's center of gravity location to assist surgical planning to maintain and/or restore coronal and sagittal plane balance, nor have they used center of gravity location to help assess surgical outcomes.

MATERIALS AND METHODS

The whole-body center of gravity (MR-COG) was determined for three subjects from magnetic resonance imaging data obtained supine. The whole-body center of gravity was also determined using subject specific (SS-COG) and literature-based (STD-COG) segment center of gravity locations in conjunction with a video motion capture system obtained supine, standing and during gait.

RESULTS

Differences existed among the three methods of determining COG locations in supine, with the SS-COG and MR-COG being most closely aligned. Results from gait data indicated typical anterior/superior and right/left COG shifts during the gait cycle. The SS-COG method consistently determined a COG location inferior to the STD-COG method; however, variation within the gait cycle was similar. Shifts in COG locations relative to a coordinate system fixed in the pelvis were more than 5 cm in the superior/inferior direction, approximately 4 cm in the anterior/posterior direction, and minimal in the left/right direction.

CONCLUSIONS

Methods have been developed to determine locations of the whole body COG in both preoperative and postoperative subjects undergoing spinal fusion surgery and controls. The methods are robust to include men and women, subjects with and without instrumentation, and subjects in various positions including gait.