Kevin P. Singer

Influence of age on cervicothoracic spinal curvature: An ex vivo radiographic survey.

OBJECTIVE To define the post-mortem cervicothoracic spinal curvature relative to age. DESIGN Spinal curvature assessment of lateral cervicothoracic radiographs. BACKGROUND A late consequence of age is the progressive accentuation of spinal curvatures, particularly the thoracic kyphosis. Little is known about the influence of the kyphosis on the alignment of the cervical spine. METHOD One hundred and seventy two lateral spinal radiographs (113 males, 59 females) were analysed using two procedures: (1) sagittal curve deformation angles were derived, according to the method of Cobb, for thoracic (T1-T12), cervical (C2-C7) and cervicothoracic junctional regions (C6-T4); and (2) the cervicothoracic curvatures were digitised (C2-T12), to derive the apex of both curves and the inflexion point. RESULTS A significantly increasing thoracic spinal curvature was determined for both genders, with the mean apex of the kyphosis close to T6. The cervical lordosis tended to flatten with increasing age, particularly in males, with the cervical apex location shifting cranially. This association was significant in older males and females. The mean location of the cervicothoracic curve inflexion point moved from T3 towards C7-T1 with increasing age. CONCLUSION The cervicothoracic spinal curvature undergoes progressive change through the lifespan with a subsequent cranial migration of the inflexion point between the thoracic kyphosis and cervical lordosis, accompanied by a similar shift in the cervical apex. RELEVANCE Sensitive measures of spinal curvature have utility in determining changes attributed to age, deformity or trauma on cervicothoracic spinal alignment. The value of assessing the location of curve inflexion lies in the ability to quantify changes in the relationship between different regions of the human spine without problems associated with identifying specific vertebral landmarks.

Normal values of plantar pressure measurements determined using the EMED-SF system

Plantar pressure-measurement technology is being increasingly used by podiatric physicians and surgeons in both clinical practice and research. The authors present normal reference-range values for peak pressure, mean pressure, and pressure-time integral obtained from 30 healthy subjects using a two-step recording technique and the EMED-SF system, as background for proposed clinical trials. Normative data of this type are essential for clinical practice in the comparison of plantar pressure-measurement values of individual patients with those of normal, asymptomatic feet.

A Review of the Use of Electro-Motor Stimulation in Human Muscles

The use of electrical stimulation in rehabilitation is a long established procedure for the management of a wide variety of musculoskeletal problems. This paper reviews important findings from studies on the electro-motor stimulation (EMS) of human muscles. It is particularly concerned with the results of EMS in normal subjects and in the rehabilitation setting, focusing on the stimulus parameters and training protocols used by various authors. A brief account is also given of some of the physiological effects of EMS on muscle. Attention is drawn to the urgent need for a more systematic approach to establish the optimal stimulation and training parameters. These factors must be considered when evaluating studies concerned with the efficacy of EMS-based rehabilitation programmes.

Transfer movement strategies of individuals with spinal cord injuries

The ability to transfer in tetraplegia is a focal point of rehabilitation. Many factors have been associated with independence in transferring, yet the majority of these are anecdotal reports. The purpose of this paper is to report preliminary findings of the study of movement strategies of individuals with spinal cord injury attempting a long sitting transfer. Analyses were made from the lateral and posterior views. Pattern recognition techniques show two distinct movement strategies in both views. These were a lift and forward flexion technique from the lateral perspective and a translatory and rotatory technique when viewed from behind. It would seem that the posterior view provides more discriminative information. It is recommended that intervention techniques, such as Functional Electrical Stimulation or orthotic devices be developed within fundamental motion analysis constructs to optimize functional outcome.

Influence of age and gender on thoracic vertebral body shape and disc degeneration: an MR investigation of 169 cases.

There are limited data detailing the pattern of age and gender‐related changes to the thoracic vertebral bodies and intervertebral discs. A retrospective MR investigation, involving T1‐weighted midsagittal images from 169 cases, was undertaken to examine age influences on the anterior wedge (anteroposterior height ratio or Ha/Hp), biconcavity (midposterior height ratio or Hm/Hp), and compression indices (posterior height/anteroposterior diameter or Hp/D) of the thoracic vertebral bodies. Disc degenerative changes in the annulus, nucleus, end‐plate and disc margin were noted on T2‐weighted sagittal images for the 169 cases, based on a 3‐level grading system. A linear age‐related decline in the Ha/Hp and Hm/Hp indices was noted. The Hp/D index increased during the first few decades of life, then decreased gradually thereafter. The prevalence of abnormal findings in the annuli, nuclei and disc margins increased with increasing age, particularly in the mid and lower thoracic discs. Greater disc degenerative changes were observed in males. These findings provide further insight into the nature of thoracic vertebral shape changes across the lifespan, and the typical patterns of degeneration of the thoracic intervertebral discs.

Morphological survey of the cervicothoracic junctional region

Study Design Vertebral morphology of the cervicothoracic junctional region was studied using the C6 to T4 vertebrae from 51 disarticulated skeletons (26 males and 25 females). Objectives Orientation of the facet joint pair relative to the plane of the superior endplate and the sagittal reference was recorded. A vertebral index was developed to compare the superior endplate surface area with the posterior vertebral body height. Summary of Background Data Vertebral morphometry was recorded for comparison with the limited published data for this region. Methods The disc‐facet angle was measured using a zygapophysial endplate protractor and the facet angle recorded from computer‐aided digitizing of photographs of each segment. Vertebral dimensions were measured using Mitutoyo digital calipers. Results A marked change in disc‐facet angle from C6 to T1 was recorded, with the incidence of right versus left asymmetry highest at the T1 level. The incidence of facet angle asymmetry greater than 10° was 24% at C6, 18% at C7, and 16% at T1. The vertebral index indicated no significant gender difference. Conclusion Consistent with other junctional regions of the spine, the cervicothoracic transition has significant morphological variations.

Velocity dependent passive plantarflexor resistive torque in patients with acquired brain injury.

OBJECTIVES This study sought to determine whether factors other than stretch reflex excitability contribute to velocity dependent passive plantarflexor resistive torque following brain injury. BACKGROUND In patients with acquired brain injury increased resistance to passive muscle lengthening commonly results from abnormal muscle contraction, secondary to disinhibition of descending motor pathways, in addition to rheologic changes within the musculo-tendinous unit. Hyper-excitable tonic stretch reflex responses (spasticity) have traditionally been considered to be the main factor influencing resistance that is velocity dependent. METHODS Ten adults with brain injury and eighteen age matched controls were studied. A computer controlled torque measurement system was utilised to evaluate resistance to dorsiflexion stretches at two velocities (5 degrees and 25 degrees s(-1)). Only stretches which did not evoke muscle contraction were included in the data analysis. The mean difference and 95% confidence limits in passive plantarflexor resistive torque at two stretch velocities, measured over a defined portion of the test movement, were compared between subject groups. RESULTS A velocity dependent increase in passive plantarflexor resistive torque was evident when the ankle was dorsiflexed past the neutral position in both subjects with brain injury and controls. However, the mean difference was approximately 10 times greater in neurologically impaired limbs compared with control values. CONCLUSIONS These data indicate that an important component of velocity dependent resistance to passive muscle lengthening in adults with brain injury can be mechanical, and unrelated to stretch induced reflex muscle contraction. RELEVANCE Increased resistive torque during rapid muscle lengthening may represent a compensatory adaptation for reduced distal motor control following brain injury. A velocity dependent increase in passive plantarflexor resistive torque has the potential to improve stability during gait and provide mechanical resistance to sudden external perturbations.

Computer-assisted curvature assessment and Cobb angle determination of the thoracic kyphosis. An in vivo and in vitro comparison.

Study Design A retrospective survey of thoracic spinal curvature compared postmortem radiographs with recent clinical films in 22 cases. Objectives This study was performed to determine whether spinal curvature measured from postmortem radiographs is a valid measure of curvature in vivo. Summary of Background Data Little quantitative data have been cited on whether sagittal plane thoracic spinal curve characteristics change after death. Methods Thoracic kyphosis was measured using the Cobb method and the mean radius of curvature from computer-assisted digitizing of the vertebral contour. Thoracic segments visualized on the chest films were referenced to the postmortem radiograph. Results and Conclusions The in vivo and in vitro measurements strongly correlated (Cobb angle r = 0.95, curvature r = 0.78). Trends decreased slightly in Cobb angle (1.3°, −2.6%) and increased slightly in curvature (10.7 mm, 4.1%). Differences were not significant, however, supporting the use of spinal curvature analysis with postmortem radiographs.

The effect of interspinous implant surgery on back surface shape and radiographic lumbar curvature

BACKGROUND Interspinous process implants, used to augment lumbar spine surgery, putatively induce a local segmental lumbar kyphosis yet few investigations outline the effect in vivo on thoracolumbar sagittal curvature. Changes in lumbar skeletal alignment and posture have traditionally relied upon radiographic and back surface spinal curvature measurements, respectively. METHODS Lumbar lordosis curvature in 10 healthy subjects (6F, 4M; mean age 36 years) and 10 interspinous implant lumbar surgery patients (5F, 5M; mean age 51 years) was assessed with rasterstereography at baseline and at 6 weeks. Skeletal lumbar lordosis in standing was measured from lateral erect radiography pre- and 6 weeks post-operatively in the surgical cohort, and compared to angulation obtained for surface lordosis curvature derived from rasterstereography. FINDINGS Repeatable measurement of standing lumbar lordosis from rasterstereographic back shape imaging in healthy volunteers and lumbar surgery cases was demonstrated. Reductions of 0.6 (NS) in healthy and 3.1 (significant, P<0.001) in surgical subjects were recorded for surface lumbar lordosis angle between the 6 week time-points. Slight flattening of the segmental angle and regional lordosis after DIAM surgery was revealed by radiography. Skeletal and surface lumbar lordosis changes were uncorrelated preoperatively (rho=0.28) and postoperatively (rho=0.26). INTERPRETATION Rasterstereography is sensitive in assessing lumbar lordosis changes in healthy and lumbar surgical individuals over time. Surgery with DIAM for lumbar pathology may result in an initial mild flattening of lordosis. Serial investigations of spinal curvature after surgery with DIAM interspinous implant are warranted in order to better understand the time-course of spinal posture changes of such cases.

Non-surgical management of ankle contracture following acquired brain injury

Background and purpose: The purpose of this study was to document the outcome of non-surgical management of equinovarus ankle contracture in a cohort of patients with acquired brain injury admitted to a specialist Neurosurgical Rehabilitation Unit. Methods: This prospective descriptive study examined all patients with a new diagnosis of moderate to severe acquired brain injury (Glasgow Coma Scale score ⩽ 12) admitted for rehabilitation over a 1 year period. Ankle dorsiflexion range and plantarflexor/invertor muscle activity were evaluated weekly during the period of hospitalization. Contracture was defined as maximal passive range of motion ⩽ 0° dorsiflexion, with the knee extended, on a minimum of two measurement occasions. Patients were retrospectively allocated to one of four treatment outcome categories according to ankle dorsiflexion range, type of intervention required and response to treatment. Results: Ankle contracture was identified in 40 of the 105 patients studied. Contracture resolved with a standard physiotherapy treatment programme, including prolonged weight-bearing stretches and motor re-education, in 23 patients. Contracture persisted or worsened in 17 of 40 cases, all of whom exhibited dystonic muscle overactivity producing sustained equinovarus posturing. Ten of 17 cases required serial plaster casting ( ± injection of botulinum toxin type A) in order to achieve a functional range of ankle motion. Remediation of ankle contracture was not considered a priority in the remaining seven patients due to the severity of their overall disability. Conclusion: The incidence of ankle contracture identified in this population was considerably less than previously reported. Reduced dorsiflexion range was remediated with standard physiotherapy treatment in over half of the cases. Additional treatment with serial casting ± botulinum toxin type-A injection was required to correct persistent or worsening contracture in one quarter of cases. Dystonic extensor muscle overactivity was a major contributor to persistent or progressive ankle contracture.