Stepping over an obstacle in patients with lumbar spinal stenosis: Trunk and lower extremities of kinematic and muscle activation normalized by double limb support. A preliminary study.

BACKGROUND

Patients with LSS tend to adopt a flexed lumbar posture and trunk position, particularly when stepping over an obstacle, as this activity alters the biomechanical demands placed on the trunk and lower extremities.

OBJECTIVE

To investigate the effects of lumbar spinal stenosis (LSS) on patients' trunk and lower-extremity kinematics, and on activities involving the gluteus medius (GMed) and vastus lateralis (VL).

METHODS

All participants (9 older adult patients with LSS and 11 control subjects) were required to negotiate an obstacle while walking. Trunk and lower-extremity kinematic data and GMed and VL activities were recorded using a synchronized 3D motion capture system and surface electromyography.

RESULTS

The thoracic (12.01∘± 8.82∘ and 16.45∘± 10.80∘) and spinal (9.92∘± 14.03∘ and 5.99∘± 15.94∘) flexion angles of the leading and trailing swing limbs were higher, and the pelvic anterior tilting angle (2.37∘± 7.76∘ and 10.38∘± 8.07∘) was lower in the LSS group than in the control group (p< 0.05). With the exception of toe-off and normalized GMed activities in the contralateral leading limb (p> 0.05), all GMed (256.73 ± 112.22%, 174.00 ± 75.79%, and 270.57 ± 114.45%, respectively) and VL (208.98 ± 124.81%, 182.97 ± 93.23%, 283.91 ± 154.71%, and 394.42 ± 108.94%, respectively) activities of the contralateral leading and trailing swing limb (heel-strike and toe-off normalized activities) were significantly higher in the LSS group than in the control group (p< 0.05).

CONCLUSIONS

Patients with LSS exhibited trunk-flexed postures when stepping over an obstacle, and these trunk alignments placed higher demands on the GMed and VL activities normalized by double-limb support during joint loading in the single-leg stance. These findings support clinical recommendations for regulating the physical activity of obstacle negotiation that may be beneficial in the management of patients with LSS.