Center of rotation analysis for thoracic and lumbar 3-column osteotomies in patients with sagittal plane spinal deformity: insights in geometrical changes can improve understanding of correction mechanics

OBJECTIVE Three-column osteotomy (3CO) is used for severe spinal deformities. Associated complications include sagittal translation (ST), which can lead to neurological symptoms. Mismatch between the surgical center of rotation (COR) and the concept of the ideal COR is a potential cause of ST. Matching surgical with conceptual COR is difficult with pedicle subtraction osteotomy (PSO) and vertebral column resection (VCR). This mismatch influences correction geometry, which can prevent maximum possible correction. The authors’ objective was to examine the sagittal correction geometry and surgical COR of thoracic and lumbar 3CO. METHODS In a retrospective study of patients with PSO or VCR for severe sagittal plane deformity, analysis of surgical COR was performed using pre- and postoperative CT scans in the PSO group and digital radiographs in the VCR group. Radiographic analysis included standard deformity measurements and regional kyphosis angle (RKA). All patients had 2-year follow-up, including neurological outcome. Preoperative CT scans were studied for rigid osteotomy sites versus mobile osteotomy sites. Additional radiographic analysis of surgical COR was based on established techniques superimposing pre- and postoperative images. Position of the COR was defined in a rectangular net layered onto the osteotomy vertebrae (OVs). RESULTS The study included 34 patients undergoing PSO and 35 undergoing VCR, with mean ages of 57 and 29 years and mean RKA corrections of 31° and 49°, respectively. In the PSO group, COR was mainly in the anterior column, and surgical and conceptual COR matched in 22 patients (65%). Smaller RKA correction (27° vs 32°, p = 0.09) was seen in patients with anterior eccentric COR. Patients with rigid osteotomy sites were more likely to have an anterior eccentric COR (41% vs 11%, p = 0.05). In the VCR group, 20 patients (57%) had single-level VCR and 15 (43%) had multilevel VCR. COR was mainly located in the anterior or middle column. Mismatch between surgical and conceptual COR occurred in 24 (69%) patients. Larger RKA correction (63° vs 45°, p = 0.03) was seen in patients with anterior column COR. Patients with any posterior COR had a smaller RKA correction compared to the rest of the patients (42° vs 61°, p = 0.007). CONCLUSIONS Matching the surgical with the conceptual COR is difficult and in this study failed in one- to two-thirds of all patients. In order to avoid ST during correction of severe deformities, temporary rods, tracking rods, or special instruments should be used for correction maneuvers.

Innovative sacropelvic fixation using iliac screws and triangular titanium implants

Purpose Sacropelvic fixation is frequently used in combination with thoracolumbar instrumentation for the correction of severe spinal deformities. The purpose of this study was to explore the effects of the triangular titanium implants on the iliac screw fixation. Our hypothesis was that the use of triangular titanium implants can increase the stability of the iliac screw fixation. Methods Three T10-pelvis instrumented models were created: pedicle screws and rods in T10-S1, and bilateral iliac screws (IL); posterior fixation and bilateral iliac screws and triangular implants inserted bilaterally in a sacro-alar-iliac trajectory (IL-Tri-SAI); posterior fixation and bilateral iliac screws and two bilateral triangular titanium implants inserted in a lateral trajectory (IL-Tri-Lat). Outputs of these models, such as hardware stresses, were compared against a model with pedicle screws and rods in T10-S1 (PED). Results Sacropelvic fixation decreased the L5-S1 motion by 75–90%. The motion of the SIJ was reduced by 55–80% after iliac fixation; the addition of triangular titanium implants further reduced it. IL, IL-Tri-SAI and IL-Tri-Lat demonstrated lower S1 pedicle stresses with respect to PED. Triangular implants had a protective effect on the iliac screw stresses. Conclusion Sacropelvic fixation decreased L5-S1 range of motion suggesting increased stability of the joint. The combination of triangular titanium implants and iliac screws reduced the residual flexibility of the sacroiliac joint, and resulted in a protective effect on the S1 pedicle screws and iliac screws themselves. Clinical studies may be performed to demonstrate applicability of these FEA results to patient outcomes.

The Effect of Prolonged Pre-Operative Halo Gravity Traction for Severe Spinal Deformities on the Cervical Spine Radiographs

Study Design: Retrospective review of consecutive series. Objective: The study sought to assess the effect of prolonged pre-operative halo gravity traction (HGT) on the c-spine radiographs Methods: Data of 37 pediatric and adult patients who underwent ≥ 12wks pre-op HGT prior to definitive spine surgery from 2013-2015 at a single site in West Africa was reviewed. Radiographic assessment of the c-spine including ADI, SVA and C2-C7 Lordosis were done at pre HGT and at 4 weekly intervals. Paired T-Test was performed to evaluate changes in these parameters during HGT. Results: 37pts, 18/19 (F/M). Average age 18.2yrs. Diagnoses: 22 idiopathic, 6 congenital, 3 Post TB, 2 NM and 4 NF. Average duration of HGT: 125 days. Baseline coronal Cobb:130 deg, corrected 30% in HGT; baseline sagittal Cobb:146 deg, corrected 32% post HGT. Baseline ADI (3.17 ± 0.63 mm) did not change at 4wks ( P > 0.05) but reduced at 8wks (2.80 ± 0.56 mm) and 12wks (2.67 ± 0.51 mm) post HGT ( P < 0.05). Baseline HGT SVA (20.7 ± 14.98 mm) significantly improved at 4wks (11.55 ± 10.26 mm), 8wks (7.54 ± 6.78 mm) and 12wks (8.88 ± 4.5 mm) ( P < 0.05). Baseline C2-C7 lordosis (43 ± 20.1 deg) reduced at 4wks (26 ± 16.37 deg), 8wks (17.8 ± 14.77 deg) and 12wks (16.7 ± 11.33 deg) post HGT ( P < 0.05). There was no incidence of atlanto-axial instability on flexion extension radiographs at any interval. Conclusion: Prolonged HGT, while providing partial correction of severe spine deformities, also appeared to have no adverse effect on atlanto-axial stability or cervical alignment. Therefore, HGT can be safely applied for several weeks in the preoperative management of severe spine deformities in pediatric/adult patients.

BEZOLD JARISCH REFLEX DURING HALO-GRAVITY TRACTION: CASE REPORT

ABSTRACT Halo-gravity traction is an option that can be used in the treatment of severe spinal deformities. The author reports a complication not yet described in the literature in which rapid correction of the deformity triggered the Bezold Jarisch reflex. Level of evidence IV; Case Series.

Clinical efficacy of short-term pre-operative halo-pelvic traction in the treatment of severe spinal deformities complicated with respiratory dysfunction

Background Halo traction has been used as an adjunctive method in the treatment of severe spinal deformities. But there are few reports on the clinical efficacy of halo-pelvic traction (HPT) in the treatment of severe spinal deformities complicated with respiratory dysfunction. This study was to evaluate the clinical efficacy and complications associated with pre-operative HPT in the treatment of severe spinal deformities with respiratory dysfunction. Methods Thirty patients with severe spinal deformities complicated with respiratory dysfunction treated with short-term pre-operative HPT were retrospectively reviewed. Inclusion criteria were: (1) patients with severe kyphoscoliosis (coronal Cobb angle or kyphosis angle ≥100°) and respiratory failure, (2) patients undergoing HPT until posterior fusion surgery. All patients underwent general anesthesia for HPT application, which the pelvic ring used in this study was a half-ring, and the rods were all placed on the anterolateral side of the truck. Results The major coronal curve scoliosis averaged 116.00 ± 16.70° and was reduced to 63.23 ± 14.00° after HPT, 46.33 ± 10.70° after surgery. The major kyphosis was 102.40 ± 27.67° and was reduced to 52.23 ± 14.16° after HPT, 42.0 ± 11.92° after surgery. A significantly increased FVC was observed after HPT (p < 0.001), with a significantly improved FVC% (p < 0.001). Similarly, a significantly increased FEV1 was also observed (p < 0.001), with a significantly improved FEV1% (p < 0.001). Conclusion This study indicated that the modified HPT could be used to help patients with severe spinal deformities complicated with respiratory dysfunction achieve significant correction in both the coronal and sagittal deformities during the pre-operative treatment period along with improved respiratory function and in the absence of severe complications.

Clinical efficacy of short-term pre-operative halo-pelvic traction in the treatment of severe spinal deformities complicated with respiratory dysfunction

Background Halo traction has been used as an adjunctive method in the treatment of severe spinal deformities. But there are few reports on the clinical efficacy of halo-pelvic traction (HPT) in the treatment of severe spinal deformities complicated with respiratory dysfunction. This study was to evaluate the clinical efficacy and complications associated with pre-operative HPT in the treatment of severe spinal deformities with respiratory dysfunction.Methods Thirty patients with severe spinal deformities complicated with respiratory dysfunction treated with short-term pre-operative HPT were retrospectively reviewed. Inclusion criteria were: (1) patients with severe kyphoscoliosis (coronal Cobb angle or kyphosis angle ≥100°) and respiratory failure, (2) patients undergoing HPT until posterior fusion surgery. All patients underwent general anesthesia for HPT application, which the pelvic ring used in this study was a half-ring, and the rods were all placed on the anterolateral side of the truck. Results The major coronal curve scoliosis averaged 116.00 ± 16.70° and was reduced to 63.23 ± 14.00° after HPT, 46.33 ± 10.70° after surgery. The major kyphosis was 102.40 ± 27.67° and was reduced to 52.23 ± 14.16° after HPT, 42.0 ± 11.92° after surgery. A significantly increased FVC was observed after HPT (p<0.001), with a significantly improved FVC% (p<0.001). Similarly, a significantly increased FEV1 was also observed (p <0.001), with a significantly improved FEV1% (p<0.001).Conclusion This study indicated that the modified HPT could be used to help patients with severe spinal deformities complicated with respiratory dysfunction achieve significant correction in both the coronal and sagittal deformities during the pre-operative treatment period along with improved respiratory function and in the absence of severe complications.

Clinical Efficacy of Short-Term Pre-Operative Halo-Pelvic Traction in the Treatment of Severe Spinal Deformities Complicated With Respiratory Dysfunction

Background Halo traction has been used as an adjunctive method in the treatment of severe spinal deformities. But there are few reports on the clinical efficacy of halo-pelvic traction (HPT) in the treatment of severe spinal deformities complicated with respiratory dysfunction. This study was to evaluate the clinical efficacy and complications associated with pre-operative HPT in the treatment of severe spinal deformities with respiratory dysfunction.Methods Thirty patients with severe spinal deformities complicated with respiratory dysfunction treated with short-term pre-operative HPT were retrospectively reviewed. Inclusion criteria were: (1) patients with severe kyphoscoliosis (coronal Cobb angle or kyphosis angle ≥100°) and respiratory failure, (2) patients undergoing HPT until posterior fusion surgery. All patients underwent general anesthesia for HPT application, which the pelvic ring used in this study was a half-ring, and the rods were all placed on the anterolateral side of the truck. Results The major coronal curve scoliosis averaged 116.00 ± 16.70° and was reduced to 63.23 ± 14.00° after HPT, 46.33 ± 10.70° after surgery. The major kyphosis was 102.40 ± 27.67° and was reduced to 52.23 ± 14.16° after HPT, 42.0 ± 11.92° after surgery. A significantly increased FVC was observed after HPT (p<0.001), with a significantly improved FVC% (p<0.001). Similarly, a significantly increased FEV1 was also observed (p <0.001), with a significantly improved FEV1% (p<0.001).Conclusion This study indicated that the modified HPT could be used to help patients with severe spinal deformities complicated with respiratory dysfunction achieve significant correction in both the coronal and sagittal deformities during the pre-operative treatment period along with improved respiratory function and in the absence of severe complications.

Experiences from treating seven adult 5q spinal muscular atrophy patients with Nusinersen

Background: The antisense oligonucleotide Nusinersen recently became the first approved drug against spinal muscular atrophy (SMA). It was approved for all ages, albeit the clinical trials were conducted exclusively on children. Hence, clinical data on adults being treated with Nusinersen is scarce. In this case series, we report on drug application, organizational demands, and preliminary effects during the first 10 months of treatment with Nusinersen in seven adult patients. Methods: All patients received intrathecal injections with Nusinersen. In cases with severe spinal deformities, we performed computed tomography (CT)-guided applications. We conducted a total of 40 administrations of Nusinersen. We evaluated the patients with motor, pulmonary, and laboratory assessments, and tracked patient-reported outcome. Results: Intrathecal administration of Nusinersen was successful in most patients, even though access to the lumbar intrathecal space in adults with SMA is often challenging. No severe adverse events occurred. Six of the seven patients reported stabilization of motor function or reduction in symptom severity. The changes in the assessed scores did not reach a significant level within this short time period. Conclusions: Treating adult SMA patients with Nusinersen is feasible and most patients consider it beneficial. It demands a complex organizational and interdisciplinary effort. Due to the slowly decreasing motor functions in adult SMA patients, long observation phases for this recently approved treatment are needed to allow conclusions about effectiveness of Nusinersen in adults.