Cervical rotational osteotomy for correction of axial deformity in a patient with ankylosing spondylitis.

PURPOSE: Severe cervical axial deformity associated with ankylosing spondylitis (AS) is rare in clinic, and there are little concerns about surgical treatment of axial deformity associated with AS. The case study aims to show the surgical technique to perform cervical rotational osteotomy. METHODS: We present the case of a young AS patient whose neck was fixed in a left-rotational posture at 18°, requiring his trunk to be turned to the right to look forward visually. This made his gait appear to be limping, inconveniencing him with great difficulty. In order to correct this deformity, we performed a novel cervical rotational osteotomy through a one-stage posterior-anterior-posterior approach. Firstly, we performed laminectomies of C7 and T1, followed by a C7/T1 facetectomy with release of the bilateral C8 nerve roots. Next, we performed C7/T1 discectomy, bony resection of the lateral body and uncovertebral joints. The head of the patient was then rotated manually, so that both his face and torso were simultaneously facing frontward. Finally, rods spanning the screws from C6 to T2 were fixed. RESULTS: Postoperatively, the patient's axial malalignment was significantly improved, and he was able to walk normally. Surgical outcomes were well maintained at a 3-year follow-up. CONCLUSION: Through this case, we hope to draw the attention to spinal axial deformity and provide a reference point in the surgical treatment of spinal axial deformity.

Global malalignment in adolescent idiopathic scoliosis: the axial deformity is the main driver.

PURPOSE: To evaluate the global alignment of non-operated subjects with adolescent idiopathic scoliosis. METHOD: A total of 254 subjects with AIS and 64 controls underwent low dose biplanar X-rays and had their spine, pelvis, and rib cage reconstructed in 3D. Global alignment was measured in the sagittal and frontal planes by calculating the OD-HA angle (between C2 dens to hip axis with the vertical). Subjects with AIS were classified as malaligned if the OD-HA was > 95th percentile relative to controls. RESULTS: The sagittal OD-HA in AIS remained within the normal ranges. In the frontal plane, 182 AIS were normally aligned (Group 1, OD-HA = 0.9°) but 72 were malaligned (Group 2, OD-HA = 2.9°). Group 2 had a more severe spinal deformity in the frontal and horizontal planes compared to Group 1 (Cobb: 42 ± 16° vs. 30 ± 18°; apical vertebral rotation AVR: 19 ± 10° vs. 12 ± 7°, all p < 0.05). Group 2 subjects were mainly classified as Lenke 5 or 6. 19/72 malaligned subjects had a mild deformity (Cobb < 30°) but a progressive scoliosis (severity index ≥ 0.6). The frontal OD-HA angle was found to be mainly determined (adjusted-R2 = 0.22) by the apical vertebral rotation and secondarily by the Lenke type. CONCLUSIONS: This study showed that frontal malalignment is more common in distal major structural scoliosis and its main driver is the apical vertebral rotation. This highlights the importance of monitoring the axial plane deformity in order to avoid worsening of the frontal global alignment.

A marker-free registration method for standing X-ray panorama reconstruction for hip-knee-ankle axis deformity assessment.

Accurate measurement of knee alignment, quantified by the hip-knee-ankle (HKA) angle (varus-valgus), serves as an essential biomarker in the diagnosis of various orthopaedic conditions and selection of appropriate therapies. Such angular deformities are assessed from standing X-ray panoramas. However, the limited field-of-view of traditional X-ray imaging systems necessitates the acquisition of several sector images to capture an individual's standing posture, and their subsequent 'stitching' to reconstruct a panoramic image. Such panoramas are typically constructed manually by an X-ray imaging technician, often using various external markers attached to the individual's clothing and visible in two adjacent sector images. To eliminate human error, user-induced variability, improve consistency and reproducibility, and reduce the time associated with the traditional manual 'stitching' protocol, here we propose an automatic panorama construction method that only relies on anatomical features reliably detected in the images, eliminating the need for any external markers or manual input from the technician. The method first performs a rough segmentation of the femur and the tibia, then the sector images are registered by evaluating a distance metric between the corresponding bones along their medial edge. The identified translations are then used to generate the standing panorama image. The method was evaluated on 95 patient image datasets from a database of X-ray images acquired across 10 clinical sites as part of the screening process for a multi-site clinical trial. The panorama reconstruction parameters yielded by the proposed method were compared to those used for the manual panorama construction, which served as gold-standard. The horizontal translation differences were 0:43 ± 1:95 mm 0:26 ± 1:43 mm for the femur and tibia respectively, while the vertical translation differences were 3:76 ± 22:35 mm and 1:85 ± 6:79 mm for the femur and tibia, respectively. Our results showed no statistically significant differences between the HKA angles measured using the automated vs. the manually generated panoramas, and also led to similar decisions with regards to the patient inclusion/exclusion in the clinical trial. Thus, the proposed method was shown to provide comparable performance to manual panorama construction, with increased efficiency, consistency and robustness.

Body height loss characterizes camptocormia in Parkinson's disease.

Axial deformities such as camptocormia or Pisa syndrome in people with Parkinson's disease (PwP) are poorly understood. The scarcity of information may result from the shortage of reliable and responsive evaluation instruments. We evaluated the body height loss (BHL) as a new measure for PwP with axial deformities. 50 PwP with axial deformity defined by an UPDRS item 28 value of at least 2 were included in this mono-center study. We measured body height while lying supine and after 1 min of standing, providing a percentage value of BHL, and compared this measure to other clinical variables. BHL depended on the Hoehn and Yahr clinical stage and correlated with clinical scales for function and mobility, but not with timely measures of the axial disorder such as age at diagnosis or duration of disease. ANOVA showed that only lumbar flexion explained the variability of BHL (F = 21.0, p < 0.0001), but not kyphosis (F = 0.4, p = 0.74) or lateroflexion (F = 0.6, p = 0.6). Re-test reliability of BHL was good with к = 0.76 (p < 0.0001). BHL resulted from the lumbar spine and the hip joint and not from the thoracic spine or lateroflexion. This observation conforms to the concept of upper-type and lower-type camptocormia with only the latter leading to a BHL. The assessment of the BHL is shown to be a well defined, easy to perform, and reliable measure for the clinical evaluation of lower-type camptocormia.