Influence of acute shortening on the spinal cord: an experimental study

A Novel "De-tension"-guided Anterior Decompression Strategy-Thoracic Anterior Controllable Antedisplacement Fusion (TACAF) for Multilevel Ossification of Posterior Longitudinal Ligament in Thoracic Spine: A Retrospective Study with at Least 2-Year Follow-Up

OBJECTIVE

To propose a novel surgical strategy-thoracic anterior controllable antedisplacement fusion (TACAF) to treat multilevel thoracic ossification of the posterior longitudinal ligament (mT-OPLL), and investigate its safety and efficacy.

METHODS

Between January 2019 and December 2021, a total of 49 patients with thoracic myelopathy due to mT-OPLL surgically treated with TACAF were retrospectively reviewed. Patients' demographic data, radiologic parameters, and surgery-related complications, modified Japanese Orthopedic Association (mJOA) and visual analog scale (VAS) scores, thoracic kyphosis (TK), kyphosis angle in fusion area (FSK), thoracic curvature, spinal cord curvature, and curvature of curved rod in surgical region, diameter, and area of the spinal cord at the most compressed level were included.

RESULTS

All patients acquired satisfactory recovery of neurologic function and overall complication rate was low at the final follow up. The mean mJOA of the laminectomy+TACAF and Full Lamina Preservation +TACAF groups, respectively, was 3.74 ± 2.05, 3.67 ± 1.95 before surgery, and 9.97 ± 0.83, 9.80 ± 0.68 at the final followed up, with the recovery rate of 84.26% ± 14.20%, 82.79% ± 10.35%, as to VAS Scores. The mean FSK was 34.50 ± 4.46,35.33 ± 3.44 before surgery, and was restored to 20.97 ± 5.70, 22.93 ± 6.34 at the final followed up respectively, as to mean TK (P < 0.05). Spinal cord curvature was improved from 34.12 ± 3.59, 33.93 ± 3.45 before surgery to 19.47 ± 3.53, 18.80 ± 3.17 at the final follow-up respectively, as to thoracic curvature (P < 0.05). In addition, the area and diameter of the spinal cord was also significantly improved at the final follow up (all P < 0.05). The curvature of the thoracic pulp and thoracic vertebra is closely related to the curvature of the rod. There was no statistically significant difference in the incidence of the pelvis and the slope value of the sacrum.

CONCLUSIONS

This strategy provides a novel solution for the treatment of mT-OPLL with favorable recovery of neurological function, the tension of spinal cord, and fewer complications.

Long-term outcome evaluation in ankylosing spondylitis with high-angle thoracolumbar kyphotic deformity corrected by one-stage single-level pedicle subtraction osteotomy augmented with Ponte osteotomy: A case series

INTRODUCTION AND IMPORTANCE

A high-angle thoracolumbar kyphotic deformity (TLKD) may complicate surgical rectification of AS patients since one-stage two-level pedicle subtraction osteotomy (PSO), which provides high-angular correction, leads to excessive blood loss, neurological deficits and fixation failures. This case series presents the long-term results of one-stage single level PSO with Ponte osteotomy (PO) in the treatment of AS patients with high-angle TLKD.

CASE PRESENTATION

This case series presents two AS patients with high kyphotic angles (KAs) of 86.1o. We collected data retrospectively from our institution's database between 2019 and 2023. A sagittal axis imbalance was the only complaint initially, no neurological deficits or other problems. A PSO augmented by PO was performed with a decompression laminectomy. Intraoperative monitoring (IOM) during reduction was used to observe neurological deficits. Blood loss at the highest rate was 1000 cc. It corrected 57.8o of KA postoperatively without neurological deficits. We found consistent results over 36 months.

CLINICAL DISCUSSION

A thorough analytical approach may help diagnose AS. One-stage single-level PSO may correct high-angle TLKD in AS patients effectively. To achieve greater angular correction, PO, a less risky osteotomy, must be added. Decompression laminectomy is vital before osteotomy and IOM is crucial during reduction to prevent nerve injury. Even with two osteotomies, there was less blood loss than previously reported. These impressive long-term results call for further research.

CONCLUSION

Combined PSO and PO with IOM efficiently magnifies the angular correction without postoperative neurological deficits or excessive blood loss in AS patients with high-angle TLKD.

Development of a sacral fracture model to demonstrate effects on sagittal alignment

PURPOSE

To develop a modeling framework to predict the secondary consequences on spinal alignment following correction and to demonstrate the impact of pedicle subtraction osteotomy (PSO) location on sagittal alignment.

METHODS

Six patients were included, and pelvic incidence (PI) was measured. Full-length standing radiographs were uploaded into PowerPoint and manipulated to model S1-S2 joint line sacral fractures at 15°, 20°, 25°, and 30°. PSO corrections with hinge points at the anterior superior corner and vertical midpoint of the L3-5 vertebral bodies were modeled. Anterior translation (AT) and vertical shortening (VS) were calculated for the six PSO locations in the four fracture angle (FA) models.

RESULTS

PI had a strong effect in the mixed AT and VS models (P < 0.001). Both AT and VS were significantly different from zero at all FA (p < 0.001), and pairwise comparisons revealed all FA were different from each other with respect to both AT and VS after adjusting for PSO location (p < 0.001), increasing as FA increased. Varying PSO location resulted in significant differences in AT when comparing all locations (p < 0.001). AT was greatest for all FA in all patients when the PSO correction was performed at the L3-AS (p < 0.001). There were significant differences in VS when comparing the L5-Mid PSO location to the L3-AS, L3-Mid, L4-AS, and L4-Mid PSO locations (p < 0.034).

CONCLUSION

PSO correction superior to a sacral fracture resulted in AT and VS of the spine. It is crucial that these changes in spinal measures be predicted and accounted for to optimize patient sagittal alignment and outcomes.

Intraoperative Neurophysiological Monitoring Alerts During Three-Column Osteotomy: Incidence and Risk Factors

PRUPOSE

To analyze the incidence and risk factors of intraoperative neurophysiological monitoring (IONM) alerts in patients undergoing three-column osteotomy.

METHODS

A total of 551 patients (340 males and 211 females) with an average age of 31.9 years undergoing posterior 3-column osteotomy were retrospectively reviewed. The coronal Cobb angle of main curve and sagittal global kyphosis were measured on preoperative standing whole spinal x-rays. The Frankel scores at preoperation, postoperation, and the last follow-up were recorded and applied for assessment of neurologic status. Surgical procedures and other factors associated with IONM alerts were analyzed.

RESULTS

A total of 98 (17.8%) IONM alerts were reported during surgery, including 82 somatosensory evoked potential alerts and 91 motor evoked potential alerts. Positive wake-up test was revealed in 57 patients (10.3%) even after prompt managements, and new neurologic deficits were observed in 50 patients (9.1%) at immediate postoperation. Of the 50 patients with new neurologic deficits at postoperation, the Frankel scores were A in 5 patients, B in 4, C in 9, and D in 32. The χ 2 test showed that patients with congenital deformities, global kyphosis >90°, vertebral column resection procedure, cervicothoracic/thoracic osteotomy, blood loss >3,000 mL, and preoperative neurologic deficit were at a higher risk of IONM alerts.

CONCLUSIONS

The incidence of IONM alerts in patients undergoing 3-column osteotomy was 17.8%. Congenital deformities, global kyphosis >90°, vertebral column resection, cervicothoracic/thoracic osteotomy, blood loss >3,000 mL, and preoperative neurologic deficit indicated high risk of IONM alerts.

Could extended laminectomy effectively prevent spinal cord injury due to spinal shortening after 3-column osteotomy?

OBJECTIVE

To explore whether the laminectomy extension can effectively prevent spinal cord injury (SCI) due to spinal shortening after 3-column osteotomy in goat models.

METHODS

A total of twenty healthy goats were included and done with 3-column osteotomy of T13 and L1 under the somatosensory evoked potential (SSEP) monitoring. The samples were divided into two groups. The first group underwent regular laminectomy while the second group underwent an extended laminectomy with an extra 10 mm-lamina cranial to L2. The SSEP measured after 3-column osteotomy was set as the baseline, and the SSEP decreased by 50% from the baseline amplitude and/or delayed by 10% relative to the baseline peak latency was set as positive results, which indicated spinal cord injury. The vertebral column was gradually shortened until the SSEP monitoring just did not show a positive result. The height of the initial osteotomy gap (the distance from the lower endplate of T12 to the upper endplate of L2), the shortened distance (△H), the number of spinal cord angulated and the changed angle of the spinal cord (△α) were measured and recorded in each group. Neurological function was evaluated by the Tarlov scores on day 2 postoperatively.

RESULTS

All the goats except one of the first group due to changes in the SSEP during the osteotomy were included and analyzed. In the first group, the height of the initial osteotomy segment and the safe shortening distances were 61.6 ± 2.6 mm and 35.2 ± 2.6 mm, respectively; the spinal cord of 5 goats was angulated (46.4 ± 6.6°), the other four goats were kinked and not angulated. In the second group, the height of the initial osteotomy segment and the safe shortening distances were 59.8 ± 1.5 mm and 43.3 ± 1.2 mm, respectively, and the spinal cord of ten goats were angulated (97.6 ± 7.2°). There was no significant difference in the height of the initial osteotomy segment between the two groups by using Independent-Samples T-Test, P = 0.095 (P > 0.05); there were significant difference in the safe shortening distance and the changed angle of the spinal cord between the two groups by using Independent-Samples T-Test (both [Formula: see text]H and [Formula: see text]α of P < 0.001), the difference between their mean were 8.1 mm and 51.2°. Significant difference was found in the number of spinal cord angulation between the two groups through Fisher's exact test (5/9 vs. 10/10, P = 0.033).

CONCLUSIONS

An additional resection of 10 mm-lamina cranial to L2 showed the satisfactory effect in alleviating SCI after 3-column osteotomy. Timely and appropriate extend laminectomy could be a promising therapeutic strategy for SCI attributable to facilitating spinal cord angulation rather than spinal cord kinking and increasing the safe shortening distance.

Partial vertebrectomy with spine shortening for old spondyloptosis at the thoracolumbar spine: a case series study and literature review

Objective

We aimed to report the surgical outcomes of serial cases and retrospectively analyze the value of partial vertebrectomy and spinal shortening in the reduction of old spondyloptosis at the thoracolumbar spine.

Methods

From 2015 to 2021, eight cases of patients who received a spinal intervention of partial vertebrectomy and spinal shortening for thoracolumbar spondyloptosis over 3 weeks post-trauma were retrospectively summarized. Medical records and surgical outcomes were extracted for clinical safety and efficacy evaluation.

Results

Acceptable reduction and immediate stabilization were achieved for all eight cases without causing iatrogenic damage to the viscera. The mean operation time was 3.7 h (range, 3.2-4.2 h) with a mean blood loss average of 1,081 ml (range, 900-1,300 ml). Postoperative stay in the spine department was an average of 11.4 days (range, 8-17 days), followed by an early rehab program. The mean visual analog scale (VAS) for low back pain decreased from 8.0 preoperatively to 1.4 at the last follow-up. The average follow-up period was 19.9 months. As for neurological function recovery, six patients with preoperative ASIA-A status remained unchanged throughout the follow-up period and improvement of one ASIA grade was noted in two patients. At the latest follow-up, sound interbody fusion as well as good alignment of the spinal column were confirmed radiologically in seven patients, while one patient encountered slight re-dislocation 3 months after surgery, but eventually achieved spinal fusion.

Conclusion

Partial vertebrectomy and spine shortening via a posterior approach showed good efficacy and safety in the management of old spondyloptosis of the thoracolumbar spine, allowing for a one-step good reduction and spinal fusion for early rehabilitation.

One-stage Spine-shortening Osteotomy Treated Severe Spinal Deformity Associated With Spinal Cord Malformations

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To evaluate the safety and efficacy of spine-shortening using 1-stage 3-column osteotomy for a severe rigid spinal deformity with a spinal cord malformation (SCM).

SUMMARY OF BACKGROUND DATA

One-stage spine-shortening osteotomy has been suggested for the treatment of a tethered spinal cord. However, the safety and efficacy of 1-stage spine-shortening osteotomy for the treatment of a severe spinal deformity with an SCM is not known.

METHODS

The records of 32 patients with a severe spinal deformity and SCM treated with spine-shortening using 3-column osteotomy from January 2010 to December 2016 were analyzed retrospectively. Intraoperative neurophysiological monitoring was used in all cases. Imaging parameters and neurological complications were analyzed to evaluate clinical safety and efficacy.

RESULTS

Spine-shortening using a 3-column osteotomy was conducted successfully in all 32 patients. The mean main coronal curve and maximum kyphotic angle were corrected from 119.8 and 119.1 degrees to 58.6 and 53.9 degrees, respectively, with the corrective rate of 51.4% and 54.3%. The mean correction loss of the major coronal curve and maximum kyphosis was 2.3 and 2.6 degrees, respectively, at a mean follow-up of 73.6 months. Intraoperative monitoring events occurred in 9 patients; of these 9 patients, 3 suffered transient SC injury, and all recovered within 1 year without suffering permanent paralysis.

CONCLUSIONS

Spine-shortening using a 3-column osteotomy seems to be safe and efficacious for treating a severe spinal deformity with an SCM. A deep understanding of the method and intensive intraoperative neuromonitoring improved the safety of this challenging and complex surgical procedure.

Evaluation of vertebral shortening and interbody fusion with short segment pedicle screw fixation for unstable thoracolumbar fractures

Background

Various operative procedures have been described for the treatment of traumatic paraplegia caused by unstable thoracolumbar fractures. We prospectively evaluated interbody fusion (IBF) with SS-PSF in these cases with regard to clinico-radiological outcome with the objectives: (1) Does IBF and short segment pedicle screw fixation (SS-PSF) prevent progression of kyphotic angle after surgery? (2) Can this procedure be safely performed in the setting of acute trauma?.

Methods

Sixteen patients suffering from traumatic paraplegia caused by acute unstable thoracolumbar fractures were enrolled prospectively and underwent IBF with SS-PSF. They were evaluated for magnitude of shortening in spine, progression of kyphotic angle, and neurological improvement by American spinal injury association scale (ASIA).

Results

Out of total sixteen, 14 patients were ASIA grade A and 2 were grade C, at the time of presentation. Thirteen out of these 14 remained grade A and one improved to B. Both the patients who had grade C involvement at the time of presentation improved to grade D at one-year follow-up. The mean blood loss was 750 ml (range; 650 ml-1150 ml). Mean kyphotic angle decreased from 20.6° (range; 13° to 37°) preoperatively to 6.2° (range; 3° to 10°) at postoperative day 2 (p = 0.002). Its mean value after 6 months was 6.5° (range; 3° to 11°). The procedure resulted in mean spinal column shortening of 18 mm (range; 16 mm-22 mm) in the spinal column. All the patients achieved bony union by a mean duration of 3.9 months (range; 3 months-6 months).

Conclusions

IBF with SS-PSF has the shortest possible instrumented construct for thoracolumbar junction fusion done by posterior approach. The interbody fusion for unstable thoracolumbar junction fractures prevents the progression of kyphotic angle post-operatively.

Level of evidence

Level 4.

Treatment of rigid post-traumatic thoracolumbar kyphosis by a novel technique of spinal joints release

OBJECTIVE

The purpose of this study was to evaluate the feasibility of a novel technique named spinal joints release (SJR) and observe its efficacy in treating rigid post-traumatic thoracolumbar kyphosis (RPTK).

METHODS

RPTK patients who were treated by SJR with facet resection, limited laminotomy, clearance of the intervertebral space, and release of the anterior longitudinal ligament through the intervertebral foramen and disc of injury segment from August 2015 to August 2021 were reviewed. Intervertebral space release, internal fixation segment, operation time, and intraoperative blood loss were recorded. The intraoperative, postoperative, and final follow-up complications were observed. An improvement in the VAS score and ODI index was observed. Spinal cord functional recovery was evaluated by American Spinal Injury Association Impairment Scale (AIS). Improvement of local kyphosis (Cobb angle) was evaluated by radiography.

RESULTS

Forty-three patients were successfully treated by the SJR surgical technique. Open-wedge anterior intervertebral disc space was performed in 31 cases, and repeated release and dissection of the anterior longitudinal ligament and callus were performed in 12 cases. There was no lateral annulus fibrosis release in 11 cases, the anterior half release of lateral annulus fibrosis in 27 cases, and complete release in five cases. There were five cases of screw placement failure in one or two side pedicles of the injured vertebrae due to excessive resection of the facets and improper pre-bending of the rod. Sagittal displacement occurred in four cases at the released segment due to the complete release of bilateral lateral annulus fibrosus. Autologous granular bone + Cage was implanted in 32 cases, and autologous granular bone was implanted in 11 cases. There were no serious complications. The average operation time was 224 ± 31 min, and intraoperative blood loss was 450 ± 225 mL. All the patients were followed up with an average of 26 ± 8.5 months. The VAS scores and ODI index improved significantly at the final follow-up. All of the 17 patients with incomplete spinal cord injury achieved more than one grade of neurological recovery at the final follow-up. An 87% correction rate of kyphosis was achieved and maintained, with the Cobb angle decreasing from 27.7° preoperatively to 5.4° at the final follow-up.

CONCLUSION

Posterior SJR surgery for patients with RPTK has the advantages of less trauma and less blood loss, and kyphosis correction is satisfactory.

Characteristics and risk factors of instrumentation failure following total en bloc spondylectomy

AIMS

The aim of this study was to investigate the incidence and characteristics of instrumentation failure (IF) after total en bloc spondylectomy (TES), and to analyze risk factors for IF.

METHODS

The medical records from 136 patients (65 male, 71 female) with a mean age of 52.7 years (14 to 80) who underwent TES were retrospectively reviewed. The mean follow-up period was 101 months (36 to 232). Analyzed factors included incidence of IF, age, sex, BMI, history of chemotherapy or radiotherapy, tumour histology (primary or metastasis; benign or malignant), surgical approach (posterior or combined), tumour location (thoracic or lumbar; junctional or non-junctional), number of resected vertebrae (single or multilevel), anterior resection line (disc-to-disc or intravertebra), type of bone graft (autograft or frozen autograft), cage subsidence (CS), and local alignment (LA). A survival analysis of the instrumentation was performed, and relationships between IF and other factors were investigated using the Cox regression model.

RESULTS

A total of 44 patients (32.4%) developed IF at a median of 31 months (interquartile range 23 to 74) following TES. Most IFs were rod fractures preceded by a mean CS of 6.1 mm (2 to 18) and LA kyphotic enhancement of 10.8° (-1 to 36). IF-free survival rates were 75.8% at five years and 56.9% at ten years. The interval from TES to IF peaked at two to three years postoperatively and continued to occur over a period of time thereafter; the early IF-developing group had greater CS at one month postoperatively (CS1M) and more lumbar TES. CS1M ≥ 3 mm and sole use of frozen autografts were identified as independent risk factors for IF.

CONCLUSION

IF is a common complication following TES. We have demonstrated that robust spinal reconstruction preventing CS, and high-quality bone grafting are necessary for successful reconstruction.Cite this article: Bone Joint J 2023;105-B(2):172-179.

Identification of injury type using somatosensory and motor evoked potentials in a rat spinal cord injury model

The spinal cord is at risk of injury during spinal surgery. If intraoperative spinal cord injury is identified early, irreversible impairment or loss of neurological function can be prevented. Different types of spinal cord injury result in damage to different spinal cord regions, which may cause different somatosensory and motor evoked potential signal responses. In this study, we examined electrophysiological and histopathological changes between contusion, distraction, and dislocation spinal cord injuries in a rat model. We found that contusion led to the most severe dorsal white matter injury and caused considerable attenuation of both somatosensory and motor evoked potentials. Dislocation resulted in loss of myelinated axons in the lateral region of the injured spinal cord along the rostrocaudal axis. The amplitude of attenuation in motor evoked potential responses caused by dislocation was greater than that caused by contusion. After distraction injury, extracellular spaces were slightly but not significantly enlarged; somatosensory evoked potential responses slightly decreased and motor evoked potential responses were lost. Correlation analysis showed that histological and electrophysiological findings were significantly correlated and related to injury type. Intraoperative monitoring of both somatosensory and motor evoked potentials has the potential to identify iatrogenic spinal cord injury type during surgery.

Global realignment after posterior vertebral column resection in severe thoracolumbar post-tubercular kyphosis: correlation with patient-reported outcomes

PURPOSE

To investigate spinal realignment in patients with severe post-tubercular kyphosis (PTK) who underwent posterior vertebral column resection (PVCR) and its correlation with patient-reported outcomes (PROs).

METHODS

Eighty-two patients were included in this study. Spinopelvic parameters (focal scoliosis (FS), coronal balance (CB), sagittal vertical axis (SVA), focal kyphosis (FK), C2-7 lordosis (CL), thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), and pelvic incidence minus lumbar lordosis (PI-LL)) and PROs (Visual Analog Scale (VAS) and Oswestry Disability Index (ODI)) were analyzed. The correlation between spinopelvic parameters and PROs was evaluated.

RESULTS

FK, FS, CL, TK, LL, and PI-LL significantly changed after surgery. FK decreased from pre-operative 108.5 ± 16.4° to 31.8 ± 4.5° at three months after surgery and increased to 38.7 ± 6.6° at final follow-up (P < 0.001). FS decreased from pre-operative 20.9 ± 2.2° to 5.1 ± 2.2° at final follow-up (P < 0.001). CL decreased from pre-operative 7.2 ± 7.3° to 3.3 ± 8.3° at final follow-up (P = 0.002). TK improved from pre-operative - 5.6 ± 7.1° to 12.9 ± 8.2° at final follow-up (P < 0.001). LL decreased from pre-operative 75.5 ± 12.6° to 45.5 ± 7.9° at final follow-up (P < 0.001). PI-LL improved from pre-operative - 24.8 ± 13.4° to 4.8 ± 9.9° at final follow-up (P < 0.001). The improvement of PROs was found to be significantly correlated with the variations of FK, CL, TK, LL, and PI-LL. The multiple regression analysis revealed that FK was an independent predictor for the improvement of VAS and ODI.

CONCLUSIONS

PVCR is effective in treating severe PTK, which can significantly improve patients' clinical and radiographic outcomes. Spine surgeons should pay more attention to reducing the residual kyphosis.

Biomechanical comparison of spinal column shortening - a finite element study

BACKGROUND

At present, research on spinal shortening is mainly focused on the safe distance of spinal shortening and the mechanism of spinal cord injury, but there is no research on the biomechanical characteristics of different shortening distances. The purpose of this study was to study the biomechanical characteristics of spine and internal fixation instruments at different shortening distances by the finite element (FE) method.

METHODS

An FE model of lumbar L1-S was established and referred to the previous in vitro experiments to verify the rationality of the model by verifying the Intradiscal pressure (IDP) and the range of motion (ROM) of the motion segment. Five element models of spinal shortening were designed under the safe distance of spinal shortening, and the entire L3 vertebra and both the upper and lower intervertebral discs were resected. Model A was not shortened, while models B-E were shortened by 10%, 20%, 30% and 50% of the vertebral body, respectively. Constraining the ROM of the sacrum in all directions, a 7.5 N ·m moment and 280 N follower load were applied on the L1 vertebra to simulate the motion of the lumbar vertebrae in three planes. The ROM of the operated segments, the Von Mises stress (VMS) of the screw-rod system, the VMS of the upper endplate at the interface between the titanium cage and the L4 vertebral body, and the ROM and the IDP of the adjacent segment (L5/S) were recorded and analysed.

RESULTS

All surgical models showed good stability at the operated segments (L1-5), with the greatest constraint in posterior extension (99.3-99.7%), followed by left-right bending (97.9-98.7%), and the least constraint in left-right rotation (84.9-86.3%) compared with the intact model. The VMS of the screw-rod system and the ROM and IDP of the distal adjacent segments of models A-E showed an increasing trend, in which the VMS of the screw-rod system of model E was the highest under flexion (172.5 MPa). The VMS of the endplate at the interface between the cage and L4 upper endplate of models A-E decreased gradually, and these trend were the most obvious in flexion, which were 3.03, 2.95, 2.83, 2.78, and 2.61 times that of the intact model, respectively.

CONCLUSION

When performing total vertebrae resection and correcting the spinal deformity, if the corrected spine has met our needs, the distance of spinal shortening should be minimized to prevent spinal cord injury, fracture of internal fixations and adjacent segment disease (ASD).

Factors influencing complications after 3-columns spinal osteotomies for fixed sagittal imbalance from multiple etiologies: a multicentric cohort study about 286 cases in 273 patients

PURPOSE

Spinal osteotomies performed to treat fixed spinal deformities are technically demanding and associated with a high complications rate. The main purpose of this study was to analyze complications and their risk factors in spinal osteotomies performed for fixed sagittal imbalance from multiple etiologies.

METHODS

The study consisted of a blinded retrospective analysis of prospectively collected data from a large multicenter cohort of patients who underwent 3-columns (3C) spinal osteotomy, between January 2010 and January 2017. Clinical and radiological data were compared pre- and post-operatively. Complications and their risk factors were analyzed.

RESULTS

Two hundred eighty-six 3C osteotomies were performed in 273 patients. At 1 year follow-up, both clinical (VAS pain, ODI and SRS-22 scores) and radiological (SVA, SSA, loss of lordosis and pelvic version) parameters were significantly improved (p < 0.001). A total of 164 patients (59.2%) experienced at least 1 complication (277 complications). Complications-free survival rates were only 30% at 5 years. Most of those were mechanical (35.2%), followed by general (17.6%), surgical site infection (17.2%) and neurological (10.9%). Pre-operative neurological status [RR = 2.3 (1.32-4.00)], operative time (+ 19% of risk each additional hour) and combined surgery [RR = 1.76 (1.08-2.04)] were assessed as risk factors for overall complication (p < 0.05). The use of patient-specific rods appeared to be significantly associated with less overall complications [RR = 0.5 (0.29-0.89)] (p = 0.02).

CONCLUSION

Spinal 3C osteotomies were efficient to improve both clinical and radiological parameters despite high rates of complication. Efforts should be made to reduce operative time which appears to be the strongest predictive risk factor for complication.

Posterior Injured Vertebra Column Resection and Spinal Shortening for Thoracolumbar Fracture Associated with Severe Spinal Cord Injury: A Retrospective Case-Control Observational Study

Background

Thoracolumbar spinal fracture associated with severe spinal cord injury (sSCI) is a kind of severe traumatic spine injury. Although various approaches are currently used to treat sSCI-related thoracolumbar fractures, the neurological function of patients has not been significantly improved by surgery.

Objective

To evaluate the therapeutic effects of the new procedure of posterior injured vertebra column resection (PIVCR) and spinal shortening for the treatment of thoracolumbar fracture associated with sSCI.

Methods

In this retrospective case-control observational study, we included 66 patients with thoracolumbar fractures associated with sSCI in our institution from January 2015 to December 2017. According to the different surgical approaches, the patients were allocated to group A (n = 32, received simple posterior decompression and fixation) and group B (n = 34, received PIVCR and spinal shortening). All patients' clinical and radiologic outcomes were collected to evaluate retrospectively. The clinical outcomes were gathered, including the intraoperative blood loss, operative time, visual analog scale (VAS) score, and American Spinal Injury Association (ASIA) impairment scale. The radiologic outcomes were collected involving the range of spinal shortening, canal encroachment, heights of the anterior edge of the vertebral body, and the Cobb angle.

Results

There was no significant difference in the two groups regarding preoperative demographic data, VAS scores, segmental kyphosis Cobb, canal encroachment, and neurological status. The range of spinal shortening in group B was an average 1.57 ± 0.40 cm and 36.45 ± 6.56% of the height of the single spinal motion segment. Due to the characteristics of the surgical procedure, group B got complete decompression of the spinal cord and better postoperative canal decompression than group A. Thus, better clinical outcomes, including neurological improvement, loss of corrective Cobb angle, and VAS improvement, were shown in group B at the follow-up investigation than those in group A (P < 0.05).

Conclusion

PIVCR and spinal shortening surgical procedure is a safe, reliable, and effective approach to treating thoracolumbar fracture associated with sSCI.

A new "de-tension"-guided surgical strategy for multilevel ossification of posterior longitudinal ligament in thoracic spine: a prospective observational study with at least 3-year follow-up

BACKGROUND CONTEXT

Multilevel ossification of the posterior longitudinal ligament in thoracic spine (mT-OPLL) is a rare but clinically significant spinal condition. Various surgical methods have been developed to address this disease. However, the outcomes are commonly unfavorable, and no standard surgical strategy has been established. To solve this problem, we introduced a new surgical strategy based on an innovative decompression concept, namely "de-tension."

PURPOSE

This study aimed to investigate the safety and efficacy of this new treatment, and to establish an improved surgical strategy.

STUDY DESIGN

A prospective observational study with at least 3 years of follow-up.

PATIENT SAMPLE

Fifty-one patients with consecutive mT-OPLL who were treated between August-2012 and June-2018 were enrolled in this study.

OUTCOME MEASURES

A modified Japanese Orthopedic Association (mJOA) scale assessing thoracic spine, recovery rate (RR), and surgical complications.

METHODS

All patients underwent 1-stage thoracic posterior laminectomy, selective OPLL resection, and spinal column shortening with/without reduction of kyphosis (dekyphosis). Initially, we recommended that when thoracic kyphosis of T1-T12 in sagittal reconstruction CT (TK) was less than 20°, no dekyphosis should be performed; when this angle was greater than 20°, dekyphosis could be conducted. Patients' demographic data, radiological findings, and intra/postoperative complications were recorded and analyzed. Neurological status was evaluated with mJOA score and RR. The correlation of preoperative TK or kyphosis angle in fusion area (FSK) with postoperative dekyphosis angle and spinal column shortening distance (SD) were respectively evaluated by Pearson correlation analysis.

RESULTS

Cerebrospinal fluid leakage (58.8%) and neurological deterioration (15.7%) were the most common complications. Average mJOA score was improved from preoperative 4.0±2.1 to 8.9±2.4 at the last follow-up, and the mean RR was 71.3±33.7%. There was no correlation between preoperative TK and SD (p=.56) or between preoperative FSK and SD (p=.21), but dekyphosis angle was significantly correlated with TK (r=0.504, p<.01) and FSK (r=0.5734, p<.01). TK of 24.6° and FSK of 23.0° were determined as the critical angles for dekyphosis, and a modified surgical strategy was formulated.

CONCLUSIONS

This new strategy provided a novel solution for mT-OPLL, and was proved to be safe and effective during long-term follow-up. Further rigorously designed large-scale prospective studies are needed to validate our findings.

A 3D-printed Personalized, Combined, Modular Pedicle Subtraction Osteotomy Guide Plate System: An Experimental Study

STUDY DESIGN

Experimental study.

OBJECTIVES

The goal of this study was to develop a threedimensional (3D)-printed pedicle subtraction osteotomy (PSO) guide plate system. A 3D model and postoperative computed tomography (CT) data were used to evaluate the accuracy of osteotomy with this system.

SUMMARY OF BACKGROUND DATA

The key to the success of spinal orthopedic treatment is an effectively performed osteotomy. A 3D-printed osteotomy plate can be used for preoperative surgical planning. Due to the anatomical complexity of the spinal region, the clinical application of 3D-printed osteotomy plates remains challenging.

METHODS

The CT scans of 10 patients with thoracolumbar spinal deformities were obtained in the digital imaging and communication in medicine (DICOM) format. The diseased vertebrae and adjacent vertebrae were reconstructed and reduced by computer- aided design software, and an osteotomy plate was designed for the diseased vertebrae. The 3D-printed spinal model and osteotomy plate were used to simulate the operation for PSO. After the operation, the vertebral body treated by osteotomy underwent a CT scan, and the findings were compared with the preoperative design to evaluate the osteotomy accuracy.

RESULTS

The new 3D guide plate and spine model were used to successfully simulate 10 cases of PSO, and the comparison of the preoperative and postoperative states indicated that the osteotomy outcomes were excellent.

CONCLUSIONS

The new 3D-printed PSO guide plate system can be used for preoperative osteotomy planning and demonstrates good accuracy. The results can be used to develop 3D-printed plans for PSO in clinical practice.

A novel technique of transpedicular opening-wedge osteotomy for treatment of rigid kyphosis in patients with ankylosing spondylitis

BACKGROUND

To investigate the effectiveness and feasibility of a novel vertebral osteotomy technique, transpedicular opening-wedge osteotomy (TOWO) was used to correct rigid thoracolumbar kyphotic deformities in patients with ankylosing spondylitis (AS).

METHODS

Eighteen AS patients underwent TOWO to correct rigid thoracolumbar kyphosis. Radiographic parameters were compared before surgery, 1 week after surgery and at the last follow-up. The SRS-22 questionnaire was given before surgery and at the last follow-up to evaluate clinical improvement. The operating time, estimated blood loss and complications were analyzed.

RESULTS

The mean operating time and estimated blood loss were 236 min and 595 ml, respectively. The mean preoperative sagittal vertical axis (SVA), thoracic kyphosis (TK), pelvic tilt (PT) and thoracolumbar kyphosis (TLK) were 158.97 mm, 51.24 mm, 43.63 mm and 41.74 mm, respectively, and decreased to 66.72 mm, 35.96 mm, 27.21 mm and 8.67 mm at the last follow-up. The mean preoperative lumbar lordosis (LL) and sacral slope (SS) were 8.30 ± 24.43 mm and 19.67 ± 9.40 mm, respectively, which increased to 38.23 mm and 28.13 mm at the last follow-up. The mean height of the anterior column of osteotomized vertebrae increased significantly from 25.17 mm preoperatively to 37.59 mm at the last follow, but the height of the middle column did not change significantly. SRS-22 scores were improved significantly at the last follow-up compared with preoperatively. Solid bone union was achieved in all patients after 12 months of follow-up, and no screw loosening, screw removal or rod breakage was noticed at the last follow-up.

CONCLUSIONS

TOWO could achieve satisfactory kyphosis correction by opening the anterior column instead of vertebral body decancellation and posterior column closing, thus simplifying the osteotomy procedure and improving surgical efficacy.

Protective effect of extended laminectomy on spinal cord injury induced by spinal shortening

This study aims to investigate the effect of extended laminectomy (EL) on spinal cord injury (SCI) caused by spinal shortening and further the best time for performing this operation and the optimal length of the additional lamina to remove. Dogs were allocated to 6 groups and all received spinal column shortening at T13 segment. Animals in the control group received non-extended laminectomy following shortening. Those in the "1-lamina EL 6h" group underwent laminectomy with an additional 1-lamina length removed 6h post shortening. For the "1.5-lamina EL 6h" and "1.5-lamina EL 12h" groups, the animals had an extra 1.5-lamina length of lamina resected at 6h and 12h, respectively, post shortening. In the "2-lamina EL 6h" and "2-lamina EL 12h" groups, an extra 2-lamina length was removed at 6h and 12h post shortening, respectively. Somatosensory evoked potential (SSEP) and neurological function were recorded periodically; spinal cord blood flow (SCBF) and nerve cell apoptosis were detected. We have discovered that resection of an additional 1-lamina length appeared not adequate to relieve the sharp kinking of the spinal cord, whereas the kinking disappeared when the laminectomy extended to an additional 2-lamina length. The "1-lamina EL 6h" and "1.5-lamina EL 12h" groups showed no significant difference, as compared with the control, in latency of SSEP, SCBF, hind-limb function and apoptosis. By contrast, significant recovery of SSEP, SCBF and hind-limb function as well as reduction of apoptosis presented in other three experimental groups. The "2-lamina EL 6h" group, in particular, showed the most prominent recovery. In conclusion, in the case of shortening of 2/3 vertebral body length with 2 laminae resected, an additional resection of two laminae at 6 h post shortening showed the best performance in alleviating SCI. Timely and adequately extended laminectomy could be a potential therapeutic strategy for SCI due to spinal shortening.

Evaluation of parallel endplate osteotomy for severe rigid spinal deformities: a retrospective analysis of 36 cases with a minimum 2-year follow-up

Background

To report on the technique and results of parallel endplate osteotomy (PEO) for severe rigid spinal deformity.

Methods

We retrospectively reviewed the clinical data of 36 patients with severe rigid spinal deformities who underwent PEO between July 2016 and December 2018 and who were followed up for at least 24 months.

Results

Following PEO, the kyphosis and scoliosis correction rates reached 77.4 ± 14.0% and 72.2 ± 18.2%, respectively. The median intraoperative estimated blood loss was 1500 mL and the median operative time was 6.8 h. The SF-36 scores of physical function, role-physical, bodily pain, general health, vitality, social function, role-emotional and mental health changed from 62 ± 28, 51 ± 26, 49 ± 29, 35 ± 30, 53 ± 28, 45 ± 30, 32 ± 34 and 54 ± 18 at baseline to 81 ± 16, 66 ± 41, 72 ± 40, 64 ± 44, 75 ± 25, 71 ± 46, 66 ± 34 and 76 ± 28 at 12 months postoperatively, 82 ± 32, 67 ± 42, 81 ± 30, 71 ± 41, 80 ± 30, 74 ± 36, 68 ± 35 and 85 ± 33 at 18 months postoperatively, and 86 ± 21, 83 ± 33, 88 ± 26, 79 ± 39, 86 ± 36, 86 ± 48, 80 ± 47 and 91 ± 39 at 24 months postoperatively, respectively.

Conclusions

PEO is an effective technique for successful correction of spinal deformities. At the two-year follow-up visit, all patients achieved better clinical results based on the SF-36 scores.

Clinical Efficacy and Safety of Controlled Distraction- Compression Technique Using Expandable Titanium Cage in Correction of Posttraumatic Kyphosis

Objective

To investigate the clinical efficacy and safety of the controlled distraction-compression technique using an expandable titanium cage (ETC) in posttraumatic kyphosis (PTK).

Methods

We retrospectively studied and collected data on 20 patients with PTK. From January 2014 to December 2017, the controlled distraction-compression technique using ETC was consecutively performed in 20 patients with PTK of the thoracolumbar zone (range, 36–82 years). Among them, nine were males and 11 were females and the mean age was 61.5 years. The patients were followed regularly at 1, 3, 6, and 12 months, and the last follow-up was more than 2 years after surgery.

Results

The mean follow-up period was 27.3±7.3 months (range, 14–48). The average operation time was 286.8±33.1 minutes (range, 225–365). The preoperative regional kyphotic angle (RKA) ranged from 35.6° to 70.6° with an average of 47.5°±8.1°. The immediate postoperative mean RKA was 5.9°±3.8° (86.2% correction rate, p=0.000), and at the last follow-up more than 2 years later, the mean RKA was 9.2°±4.9° (80.2% correction rate, p=0.000). The preoperative mean thoracolumbar kyphosis was 49.1°±9.2° and was corrected to an average of 8.8°±5.3° immediately after surgery (p=0.000). At the last follow-up, a correction of 11.9°±6.3° was obtained (p=0.000). The preoperative mean back visual analog scale (VAS) score was 7.9±0.8 and at the last follow-up, the VAS score was improved to a mean of 2.3±1.0 with a 70.9% correction rate (p=0.000). The preoperative mean Oswestry disability index (ODI) score was 32.3±6.9 (64.6%) and the last follow-up ODI score was improved to a mean of 6.85±2.9 (3.7%) with a 78.8% correction rate (p=0.000). The overall complication was 15%, with two of distal junctional fractures and one of proximal junctional kyphosis and screw loosening. However, there were no complications directly related to the operation.

Conclusion

Posterior vertebral column resection through the controlled distraction-compression technique using ETC showed safe and good results in terms of complications, and clinical and radiologic outcomes in PTK. However, to further evaluate the efficacy of this surgical procedure, more patients need long-term follow-up and there is a need to apply it to other diseases.

Urodynamic evaluation of bladder function in patients with urinary incontinence secondary to congenital tethered cord syndrome after homogeneous spinal-shortening axial decompression procedure

OBJECTIVE

To evaluate the effect of homogeneous spinal-shortening axial decompression procedure (HSAD) on bladder function in patients with spina bifida tethered syndrome.

METHODS AND MATERIALS

Patients with tethered spinal cord syndrome were collected prospectively, and all patients were treated with lumbar HSAD. Patients' urodynamic evaluation mainly included detrusor function, sphincter function, sphincter coordination (Ig TLR, ratio of tension and loose of urethral sphincter), and bladder compliance. Meanwhile, all patients were followed up with ICI-Q-SF, SF-12, and Rantala scores.

RESULTS

Twenty-four patients were included, with the average age of 27 ± 16 years. At the final follow-up, patients' detrusor function, sphincter function, sphincter coordination, and bladder compliance, were all improved dramatically (all P < 0.01). The preoperative SF-12 score, ICQ, and Rantala score were [52.16 ± 5.64, 14.11 ± 5.25, 7.84 ± 4.87], whereas the postoperative mean was [33.53 ± 3.53, 9.05 ± 4.89, 15 ± 3.77] (P < 0.01, respectively). According to objective evaluation, 16.7% of them recovered to normal. According to the subjective evaluation, 25% of the patients returned to normal. Only one patient (4.2%) deteriorated. Limitations include none-randomized controlled design and limited patient samples.

CONCLUSIONS

The HSAD can significantly restore the bladder function in patients with long-term urinary incontinence.

Enhanced Safety of Pedicle Subtraction Osteotomy Using Intraoperative Ultrasound

BACKGROUND

Pedicle subtraction osteotomy (PSO) can improve sagittal alignment but carries risks, including iatrogenic spinal cord and nerve root injury. Critically, during the reduction phase of the technique, medullary kinking or neural element compression can lead to neurologic deficits.

METHODS

We describe 3 cases of thoracic PSO and evaluate the feasibility, findings, and utility of intraoperative ultrasound in this setting.

RESULTS

Intraoperative ultrasound can provide a visual assessment of spinal cord morphology before and after PSO reduction and influences surgical decision making with regard to the final amount of sagittal plane correction. This modality is particularly useful for confirming ventral decompression of disc-osteophyte complex before reduction and also after reduction maneuvers when there is kinking of the thecal sac but uncertainty about the underlying status of the spinal cord. Intraoperative ultrasound is a reliable modality that fits well into the technical sequence of PSO, adds a minimal amount of operative time, and has few limitations.

CONCLUSIONS

We propose that intraoperative ultrasound is a useful supplement to standard neuromonitoring modalities for ensuring safe PSO reduction and decompression of neural elements.

Spinal shortening osteotomy for adult tethered cord syndrome evaluated by intraoperative ultrasonography

BACKGROUND

Spinal shortening osteotomy (SSO) reduces the tension indirectly in the spinal cord and minimizes perioperative complications. However, the most effective and safe length to which the spine can be shortened is still unknown. In our practice, we use somatosensory-evoked potentials, motor-evoked potentials, and intraoperative ultrasonography when performing SSO. This study aimed to introduce the clinical outcomes of our SSO technique for tethered cord syndrome (TCS) in adults.

METHODS

This retrospective study included 7 adult patients (2 males and 5 females) with TCS treated between December 2010 and December 2018. The average age and average preoperative duration were 40 and 5 years, respectively. All patients received SSO with somatosensory-evoked potentials, motor-evoked potentials, and ultrasonography. After surgery, all patients were followed for an average of 4 years.

RESULTS

The mean operation time was 328 (284-414) min for SSO. The mean blood loss was 828 ml (501-1252 ml). Postoperative bony fusion was confirmed in all patients. Postoperative computed tomography (CT) demonstrated an average of 16 mm (11-20 mm) of spinal column shortening, compared with preoperative CT. Clinical improvements were obtained in all 7 cases, and there was no case of exacerbation. An indicator of shortening is that the ultrasonography gives pulsation and relaxation of the spinal cord. There were no abnormalities observed while monitoring the spinal cord.

CONCLUSIONS

Spinal shortening should be done under somatosensory-evoked potentials, motor-evoked potentials, and intraoperative ultrasonography to obtain safe and sufficient shortening.

Surgical management of complex post-tuberculous kyphosis among African patients: clinical and radiographic outcomes for a consecutive series treated at a single institution in West Africa

STUDY DESIGN

Retrospective review of consecutive series.

OBJECTIVE

To assess the clinical and radiographic outcomes after surgical management of post-tuberculous kyphosis. Post-tuberculous (TB) kyphosis can lead to progressive pulmonary and neurological deterioration. Surgery is indicated to decompress neural elements and correct the spine deformity. Although posterior vertebral column resection (PVCR) has been established as the treatment of choice for severe TB kyphosis, there is paucity of studies on the clinical outcomes among patients treated in West Africa.

METHODS

Clinical and radiographic data of 57 patients (pts) who underwent surgical correction of post-TB kyphosis at a single site in West Africa between 2013 and 2018 (≥ 2-year follow-up in 36 pts, ≥ 1-year FU in 21 pts). Pre- and post-op SRS scores and radiographic outcomes were compared using Paired t test.

RESULTS

57 patients, 36M:21F. Mean age 19 (11-57 years). 22/57 pts (39.3%) underwent pre-op halo gravity traction (HGT) for an average duration of 86 days (8-144 days). HGT pts had a higher baseline regional kyphosis (125.1 ± 20.9) compared to non-HGT pts (64.6 ± 31.8, p < 0.001). Post-HGT regional kyphosis corrected to 101.2 ± 23 (24° correction). 53 pts (92.9%) underwent posterior-only surgery and 4 (7.0%) combined anterior-posterior surgery. 39 (68.4%) had PVCR, 11 (19.3%) PSO, and 16 (28.1%) thoracoplasty. Intraoperative neuromonitoring (IOM) signal changes occurred in 23/57 pts (≈ 40%), dural tear in 5 pts (8.8%), pleural tear in 3 pts (5.3%), ureteric injury in 1 pt (1.7%), and vascular injury in 1 pt (1.7%). Post-op complications included four (7.0%) infection, three (5.3%) implant related, two (3.5%) radiographic (one PJK and one DJK), one (1.7%) neurologic, one (1.7%) wound problem, and two (3.5%) sacral ulcers. IOM changes were similar in the VCR (48.7%) and non-VCR (23.5%) pts, p > 0.05. Complication rates were similar among HGT and non-HGT groups. Significant improvements from baseline were seen in the average SRS Total and domains scores and radiographic measurements for patients who attained 2-year follow-up.

CONCLUSION

PVCR ± HGT can provide safe and optimal correction in cases of severe post-TB kyphosis with good clinical and radiographic outcomes in underserved regions.

Transpedicular bi-vertebrae wedge osteotomy in treatment of post-tubercular spinal deformity: a retrospective study

Background

In the late stage of spinal tuberculosis, the bony destruction and vertebral collapse often leads to significant kyphosis, presenting clinically as a painful gibbus deformity, with increased instability, vertebral body translations and increased risk of neurologic involvement. Spinal osteotomy is thought to be suitable for most patients with severe rigid kyphosis. The aim of this study was to evaluate the efficacy of transpedicular bi-vertebrae osteotomy technique in the patients with Pott’s kyphosis and other post-tubercular spinal deformity.

Methods

Between January 2012 and December 2015, 18 patients with post-tubercular spinal deformity underwent the transpedicular bi-vertebrae wedge osteotomy, with a minimum follow up of 27.0 months. Preoperative and postoperative kyphotic angle, sagittal plane parameters (TK for thoracic deformity, TLK for thoracolumbar and LL for lumbar deformity) and sagittal vertical axis (SVA) were measured. Oswestry Disability Index (ODI), Visual analog scale (VAS) and modified American Spinal Injury Association grading (ASIA) of preoperative and final follow-up were documented and compared.

Results

The average operation time was 305 minutes (range, 200–430 minutes) with a mean intraoperative blood loss of 425 mL (range, 200-700 mL). The kyphotic angles decreased from 80.3° (range, 28.5°-130.8°) preoperatively to 26.1° (range, 7.0°-63.3°) at the final follow-up (P<0.01). The mean VAS score was reduced from preoperative 5.2(range, 2-9) to 0.9(range, 0-2, P<0.01) and the ODI improved from 55.3% (range, 46%-76%) to 6.3% (range, 2%-18%, P<0.01). At final follow-up, there was radiographic evidence of solid fusion at the osteotomy site and fixed segments in all patients. Neurological function improved from ASIA scale D to E in 7 patients, C to D in 3 patients.

Conclusions

Our results suggest that transpedicular bi-vertebrae wedge osteotomy is a safe and effective treatment option for post-tubercular spinal deformity. This technique achieves satisfying correction and fusion rates with adequate decompression of neurological elements.

Avoiding Radical Removal of Posterior Elements in Posterior Vertebral Column Resections: A Modified Schwab Grade 6 Osteotomy for Severe Post-Tuberculous Kyphotic Deformity

OBJECTIVE

Posterior vertebral column resection (PVCR) is a versatile technique for correction of severe and rigid spinal deformities, but the high rate of neurological complications is a major disadvantage of this procedure. This study aimed to describe a modified PVCR technique for safe treatment of severe post-tuberculous kyphotic deformity.

METHODS

Four consecutive patients with severe post-tuberculous kyphosis underwent modified PVCRs. Radical removal of the posterior elements was avoided by performing laminectomy in stages, and the posterior vertebral wall and the bases of the spinous processes were maintained throughout the procedure. Perioperative clinical presentation, imaging data, and operative variables were recorded.

RESULTS

Desirable efficacy and clinical outcomes were obtained, including satisfactory correction rates and low estimated blood loss. Neurological status improved in all patients with preoperative neurological deficits, and no postoperative neurological complications were reported.

CONCLUSIONS

Modified PVCRs could prevent excessive handling or overstretching of the spinal cord, reduce bleeding, and provide more security in the correction of severe spinal deformities. Our initial experience showed that this modified procedure might be an alternative to conventional Schwab grade 6 osteotomy for the correction of severe post-tuberculous kyphotic deformity.

Pedicle Subtraction Osteotomy for Deformity Correction in the Upper Cervical Spine: A Technical Note

BACKGROUND

 Kyphosis is the most common deformity of the cervical spine leading to development of severe disabilities. In case of fused kyphosis, surgical treatment can be demanding and often requires multiple-step procedures for adequate correction. We present a technique of single-stage pedicle subtraction osteotomy (PSO) of C3 to treat a patient with fused kyphosis of C2 and C3 causing spinal stenosis with subsequent myelopathy.

METHODS

 A 53-year-old man presented with progressive myelopathy not able to walk with 6/18 points on the modified Japanese Orthopedic Association scale. Horizontal gaze was lost due to cervical kyphosis. Magnetic resonance imaging (MRI) revealed a cervical kyphosis causing stenosis, cord compression, and kinking; computed tomography (CT) showed substantial anterior and posterior fusion of C2 and C3.

RESULTS

 Surgery included decompression via laminectomy of C2 to C6 in combination with PSO of C3 and additional dorsal instrumentation of C2 to C6. Cervical spinal alignment was corrected, as the C2-C4 Cobb angle was reduced from 48.9 to 20.6 degrees. Horizontal gaze was restored. Postoperative MRI demonstrated full decompression of the cord without kinking of the vertebral arteries. No complications were noted. The patient recovered well with restoration of his ability to walk.

CONCLUSION

 Single-stage pedicle subtraction closing wedge osteotomy in the upper cervical spine, although a demanding surgical procedure, is an alternative treatment option in selected cases of fused and severe cervical kyphosis. In contrast to multiple-step approaches, the single-stage procedure could reduce operating time and may thus decrease complications.

Is detethering necessary before deformity correction in congenital scoliosis associated with tethered cord syndrome: a meta-analysis of current evidence

PURPOSE

To compare the clinical and radiological outcomes in patients with congenital scoliosis (CS) and tethered cord syndrome (TCS) undergoing deformity correction with (NI group) versus without (NNI group) prior neurosurgical intervention aimed at detethering the cord.

METHODS

A systematic review and meta-analysis were performed. The databases PubMed, Embase and Google Scholar were searched until March 2020. Inclusion criteria was studied describing performance of deformity correction and fusion surgery for congenital scoliosis with tethered cord syndrome with or without prior detethering procedure. Studies describing growth sparing procedures or congenital scoliosis associated with non-tethering pathologies such as syrinx were excluded. Case reports and series with less than 10 subjects were also excluded. NIH quality assessment tool was used for assessing quality of individual study.

RESULTS

Sixteen studies were included for analysis of which eight were found to be retrospective case series (level IV evidence) and retrospective case-control studies (level III evidence) each. Overall proportional meta-analysis found no significant difference in correction rate, operative duration, blood loss or complication rate between the NI and NNI groups. However, subgroup analysis performed after inclusion of only level III evidence studies revealed significantly lesser operative duration and blood loss with comparable correction and complication rate in NNI group.

CONCLUSION

Deformity correction and fusion surgery may be performed safely and effectively in CS with TCS patients without the need of a prior detethering procedure.

A preliminary study of spinal cord blood flow during PVCR with spinal column shortening: A prospective clinic study in severe rigid scoliokyphosis patients

Posterior vertebral column resection (PVCR) was the most powerful technique for treating severe rigid spinal deformity, but it has been plagued with high neurologic deficits risk. The fluctuations of spinal cord blood flow (SCBF) play an important role in secondary spinal cord injury during deformity correction surgery.The objective of this study was to first provide the characteristic of SCBF during PVCR with spinal column shortening in severe rigid spinal deformity.Severe rigid scoliokyphosis patients received PVCR above L1 level were included in this prospective study. Patients with simple kyphosis, intraspinal pathology and any degree of neurologic deficits were excluded. The deformity correction was based on spinal column shortening over the resected gap during PVCR. Laser Doppler flowmetry was used to monitor the SCBF at different surgical stages.There were 12 severe rigid scoliokyphosis patients in the study. The baseline SCBF was 316 ± 86 perfusion unite (PU), and the SCBF decreased to 228 ± 68 PU after VCR (P = .008). The SCBF increased to 296 ± 102 PU after the middle shortening and correction which has a 121% increased comparison to the SCBF after VCR (P = .02). The SCBF will slightly decrease to 271 ± 65 PU at final fixation. The postoperative neural physical examination of all patients was negative, and the MEP and SSEP of all patients did not reach the alarm value during surgery.These results indicate that PVCR is accompanied by a change in SCBF, a proper spinal cord shortening can protect the SCBF and can prevent a secondary spinal cord injury during the surgery.

Treatment of Spinal Tuberculosis of GATA Type III: Primary Posterior Debridement Combined with Osteotomy Parallel to the Endplates for Reconstruction

To evaluate the curative effect of one‐stage posterior debridement and osteotomy parallel to the endplates for reconstruction, deformity correction, and tuberculosis control on treating the spinal tuberculosis of graded GATA III. From July of 2012 to December of 2017, there were 36 cases from the Second Hospital of Shanxi Medical University with thoracic and lumbar tuberculosis graded GATA III, in which we used osteotomy parallel to the endplates and reconstruction for treatment,16 for males and 20 for females. The local Cobb angles of kyphosis of all patients are greater than or equal to 20.The age varied from 28 months to 72 years with an average of 38.8 years. There were 15 cases of thoracic segment, 12 cases of thoracolumbar segment (T₁₁‐L₂), 9 cases of lumbar segment. Preoperative results of ASIA were 3 cases of grade C,5 cases of grade D and 28 cases of grade E with an average kyphosis Cobb angle of 37.21 ± 3.28. The visual analogue scale(VAS) scores preoperatively were 0‐8 points (averaged 5.58 ± 1.66 points). All the patients had paraspinal abscesses. After completing the preoperative examinations and evaluations, the osteotomy parallel to the endplates and reconstruction were executed. We made a statistical analysis of the Cobb angles, visual analogue scale(VAS) scores, erythrocyte sedimentation rate (ESR), C‐reaction protein(CRP), and ASIA grades before and after the surgery. The following‐up time varied from 12 to 24 months, with an average of 18 months. The VAS score improved from 5.58 ± 1.66 before the surgery to 3.25 ± 0.92 one month after the surgery and 2.12 ± 0.73 at the last follow‐up. The Cobb angles decreased from 37.21° ± 3.28° before the surgery to 5.72°± 2.66° one month later and 5.99° ± 1.92° at the last follow‐up. The ESR decreased from 55.34 ± 1.72 mm/1 h before the surgery to 28.22 ± 3.76 mm/1 h one month later and 11.54 ± 0.46 mm/1 h at the last follow‐up. The CRP decreased from 35.22 ± 2.46 mg/L before to 12.67 ± 2.82 mg/L and 4.50 ± 2.11 mg/L at the last follow‐up. The results of the last ASIA grades were 1 case of grade D and 35 cases of grade E. The one‐stage posterior debridement and osteotomy parallel to the endplates for patients with spinal tuberculosis of graded GATA III are not only beneficial to spinal reconstruction, but also obtain ideal reconstuction effects.

Relationship between the laminectomy extension and spinal cord injury caused by acute spinal shortening: goat in vivo experiment

OBJECTIVE

To investigate the relationship between different types of laminectomy extension and spinal cord injury subsequent to acute spinal shorting after 3-column osteotomy in living goat model.

METHODS

A total of 18 healthy goats were selected, and a procedure of bivertebral column resections and total laminectomy of T13 and L1 was completed followed by different laminectomy extensions under the somatosensory evoked potential (SSEP) monitoring. The samples were divided into three groups according to types of subsequent laminectomy extension. In the first group (enlarged resection of upper lamina group), laminectomy extension was performed on 10 mm caudal to T12; in the second group (equidistant enlarged resection of upper and lower lamina group), laminectomy extension was performed on 5 mm caudal to T12 and 5 mm cranial to L2 simultaneously; and in the third group (enlarged resection of lower lamina group), laminectomy extension was performed on 10 mm cranial to L2. The SSEP measured after vertebral resection was set as the baseline, and the SSEP decreased by 50% from the baseline amplitude and/or delayed by 10% relative to the baseline peak latency was set as positive results, which indicated spinal cord injury. Spinal column was gradually shortened until the SSEP monitoring just did not show a positive result. The shortened distance (ΔH) and the changed angle of the spinal cord buckling (Δα) were measured in each group. Neurologic function was recorded by the Tarlov scores at 2 days after the surgery.

RESULTS

The safe shortening distances of three groups were 38.6 ± 1.2 mm, 41.5 ± 0.7 mm, 43.7 ± 0.8 mm, respectively; the corresponding changed angles of the spinal cord buckling were 62.8 ± 6.9°, 82.8 ± 7.5°, and 98.5 ± 7.0°. Significant differences of ΔH and Δα were found among the three groups by LSD multiple comparison test (P < 0.05). Strong correlation between ΔH and Δα was shown in each group by Pearson's correlation test.

CONCLUSIONS

Different laminectomy extensions after 3-column osteotomy have different effects on the prevention of SCI caused by acute spinal shortening. The enlarged resection of lower lamina is superior to equidistant enlarged resection of upper and lower laminas which is superior to enlarged resection of upper lamina in preventing SCI. These slides can be retrieved under Electronic Supplementary Material.

Safe range of shortening the middle thoracic spine, an experimental study in canine

PURPOSE

To determine the safe range of shortening the spinal column at middle thoracic spine and to observe the changes in blood-spinal cord barrier (BSCB), microglia/macrophage activation and inducible nitric oxide synthase (iNOS) activity after shortening-induced spinal cord injury.

METHODS

Dogs were allocated to four groups. Group A (control) underwent laminectomy of T7 without shortening the spinal column. Groups B, C and D had 1/3, 1/2, and 2/3 of T7 resected, respectively, followed by spinal shortening. Somatosensory evoked potential (SSEP) and hind-limb function were recorded periodically for 14 days after operation. Spinal cord blood flow (SCBF) and BSCB were detected at the acute phase of shortening. Microglia/macrophage reactions and iNOS activity were observed by immunohistochemistry.

RESULTS

Shortening of 1/3 of a vertebral height caused no significant changes in SSEP and hind-limb function after operation, whereas shortening of 1/2 of the height caused SSEP abnormality and paraparesis, and severe neurologic deficit of hind-limb was observed when the shortening reached 2/3 of the height. SCBF increased temporarily and showed a trend of recovery when the shortening was within 1/2 of a vertebral segment height. When it reached 1/2 or 2/3 of the height, SCBF at 6 h post-operation was 86.33% or 74.95% of the baseline, and an increasing BSCB permeability was observed. In the subsequent 7 days, obvious activation of macrophage and increased number of iNOS-positive cells were observed.

CONCLUSION

It is safe to shorten the spinal cord within 1/3 of a vertebral height in middle thoracic spine under two-segment laminectomy in canine. The BSCB disruption, macrophage activation, and increased iNOS activity were observed in the acute phase of the injury. These slides can be retrieved under Electronic Supplementary Material.

Total en bloc spondylectomy of T11 and spine shortening performed on a 17-month-old patient: art of the possible

STUDY DESIGN

Case report.

PURPOSE

The authors used spine shortening as an alternative strategy to intercalary graft fixation to restore permanent spine stability for a 17-month-old infant who received total en bloc spondylectomy (TES) of T11 to treat an embryonic rhabdomyosarcoma. TES involves complete removal of vertebra, compensated by spine reconstruction using intercalary allografts and permanent posterior instrumentation, which is not possible for skeletally immature patients with high growth potential and non-ossified vertebrae.

METHODS

Surgery was performed over two consecutive days. During the first day, the tumor was released from its dorsal attachments through the posterior approach. During the second day, the tumor was dissected and excised through the anterior approach, leaving a gap between T10 and T12. The two vertebrae were then drawn toward each other until the gap was bridged. The dural sac slipped into the canal under T10 and T12 with no observable kinking.

RESULTS

Fifteen weeks after surgery, thoraco-abdominal CT confirmed fusion of the T10 and T12 vertebral bodies. Three years later, the patient lives a normal life with no major neurological deficits or recurrence of sarcoma.

CONCLUSIONS

This case report is the first to demonstrate the feasibility of TES with spine shortening of an entire thoracic segment without spine kinking or damage in an infant. This unprecedented surgical technique allowed complete removal of an embryonic rhabdomyosarcoma, while granting rapid stability and growth potential.

LEVEL OF EVIDENCE

IV.

Effect of Spinal Shortening for Protection of Spinal Cord Function in Canines with Spinal Cord Angulation

Background

Posterior vertebral column resection (PVCR) has been widely used as a treatment for severe spinal deformity. By using the canine model of vertebral column resection, this study explored the effect of spinal shortening on blood flow and function of the spinal cord during spinal cord angulation.

Material/Methods

The canine model of L1 vertebral column resection was constructed with the PVCR technique. The canines were divided into 5 groups according to the degree of shortening: the 0/4 group, the 1/4 group, the 2/4 group, the 3/4 group, and the control group. Spinal cord blood flow, neuroelectrophysiology, HE staining, nitric oxide, and endothelin-1 were measured during the procedure of vertebral column resection and spinal cord angulation.

Results

The results showed that, in the 1/4 group and the 2/4 group, the blood flow of the spinal cord decreased by 16.5% and 10.6%, respectively, with no obvious damage in the spinal cord; in the 0/4 group and the 3/4 group, the blood flow decreased by 23.5% and 23.1%, respectively, with significant damage in the spinal cord.

Conclusions

When the spinal cord is shortened by 1/4 to 2/4, the tolerance of the spinal cord can increase and spinal cord injury resulting from angulation can be avoided. However, when the shortening reaches 3/4, it is harmful to the spinal cord. Proper shortening of the spinal cord by 1/4 to 2/4 may increase the tolerance of the spinal cord to the damage caused by angulation during PVCR.

Vertebral column resection for post tuberculosis severe kyphotic deformity: Results of 5 year follow-up

Background

Spinal TB is endemic in our study region and many patients present with severe kyphotic deformities and neurological deficit. We corrected such deformities with all posterior single stage surgeries. This study was undertaken to evaluate the results, efficacy and safety of this technique.

Methods

Deformity correction of 16 patients was done during January 2012 to December 2014. All patients underwent posterior only approach for vertebral column resection at peri-apical region, posterior instrumentation with pedicular screws and anterior reconstruction using mesh cage. Postoperative X-ray films were evaluated. All patients were followed up at six weeks, 12 weeks, 18 weeks, six months and yearly thereafter. At follow-up patients were evaluated neurologically and radio-graphically.

Results

Mean age of the patients was 19.43 years. (Range 3-37) An average 1.62 vertebrae were excised and 5.93 vertebral levels were instrumented. Mean blood loss was 1013 ml and the mean duration of surgery was 6.78 h. The decrease in mean kyphotic deformity from preoperative 90.08⁰ to postoperative 38.06⁰ was statistically significant. (P < 0.000) Mean percentage correction was 57.59%. No pseudoarthrosis was found on X-rays. The decrease in Oswestry's Disability Index was from 55.43 to 10.06 was statistically significant. (P < 0.000) Two patients had neurological complications and one patient had wound complication.

Conclusion

The safety and efficacy of Posterior VCR technique for post tuberculosis severe kyphotic deformity is favorable with no severe late stage complications. Excision of ribs, careful handling of cord and gradual correction of deformity with good hemostasis is important.

Safe Limit of Shortening of the Spinal Cord in Thoracolumbar Bivertebral Column Resections: An Experimental Study in Goats

OBJECTIVE

To clarify the safe limit of shortening of the spinal cord in thoracolumbar bivertebral column resection in a goat model.

METHODS

Ten healthy goats were selected for the experiment. Radiographs were taken before surgery to measure the height of T13, L1, and the initial osteotomy segment (distance from the lower end plate of T12 to the upper end plate of L2). A procedure of thoracolumbar bivertebral column resection (T13 and L1) was completed under the monitoring of somatosensory evoked potential (SSEP) monitoring. The SSEP measured after vertebral resection was set as the baseline. SSEPs decreased by 50% from the baseline amplitude and/or delayed by 10% relative to the baseline peak latency were set as positive results, indicating spinal cord injury. The initial height of the osteotomy gap was measured first and the spinal column was gradually shortened until the SSEP monitoring did not show a positive result. Then the height of the osteotomy gap was recorded again. The safe limit of shortening was measured and recorded when any morphologic change of the spinal cord was observed. Hindlimb function was evaluated by the Tarlov scores on day 2 postoperatively.

RESULTS

The safe limit of shortening of the spinal cord in thoracolumbar bivertebral columns resection was 35.2 ± 2.6 mm, which was roughly equal to 127.6% of the mean osteotomy vertebral height and 57.1% of the initial osteotomy gap height. Pearson correlation test showed that the safe limit of shortening of the spinal cord was correlated with the height of T13, the height of L1, the mean height of T13 and L1, and the height of the initial osteotomy gap.

CONCLUSIONS

The safe limit of shortening distance of the bivertebral column resection was roughly equal to 127.6% of the mean osteotomy vertebral height and 57.1% of the initial osteotomy gap height with good correlation. Moreover, the safe limit of shortening distance of the bivertebral column resection was longer than that in single vertebral column resection. Increasing the number of vertebrae resected may prevent spinal cord injury because of excessive shortening.

Clinical results and surgery tactics of spinal osteotomy for ankylosing spondylitis kyphosis: experience of 428 patients

OBJECTIVE

To report the clinical results and surgical tactics of spinal osteotomy for ankylosing spondylitis (AS) kyphosis based on the experiences of 428 patients.

METHODS

From January 2003 to January 2015, a total of 428 patients suffering from AS kyphosis who underwent a one- or two-level pedicle subtraction osteotomy (PSO) or vertebral column decancellation (VCD) osteotomy in our hospital were reviewed. Pre- and postoperative radiological parameters and the chin-brow vertical angle (CBVA) were measured. Intraoperative, postoperative, and general complications were recorded.

RESULTS

All patients could walk with horizontal vision and lie on their backs postoperatively. The pre- and postoperative average global kyphosis (GK) angles were corrected from 82.6 to 12.7° (p = 0.000) in the two-level group and from 55.8 to 9.6° (p = 0.000) in the one-level group, respectively. The mean sagittal vertical axis (SVA) improved from 29.4 to 8 cm (p = 0.000) in the two-level group and from 18.0 to 4.3 cm (p = 0.000) in the one-level group. The CBVA improved from 68.3 to 8.2° (p = 0.000) in the two-level group and from 46.2 to 4.2° (p = 0.000) in the one-level group. Although no major acute complications such as death or complete paralysis occurred, the complication rate was 6.5% in the one-level group and 23.6% in the two-level group.

CONCLUSION

Spinal osteotomy, such as PSO and VCD, can improve the quality of life of AS patients as well as correct kyphotic deformities. The one-level spinal osteotomy showed a lower complication rate, while two-level spinal osteotomy was a relatively aggressive procedure that was more suitable in correcting severe AS kyphotic deformities.

Modified Closing-Opening Wedge Osteotomy to Correct Kyphosis in Ankylosing Spondylitis

Background

The aim of this study was to analyze the clinical and radiological outcomes of modified closing-opening wedge osteotomy (mCOWO) for correcting kyphosis in ankylosing spondylitis (AS) patients.

Material/Methods

From April 2012 to April 2017, records of consecutive patients who underwent mCOWO were reviewed. The clinical and radiological outcomes were analyzed preoperatively, postoperatively, and at the most recent follow-up.

Results

Eleven AS patients underwent mCOWO, with a mean follow-up of 19.4 months (range, 12–45 months). The average sagittal vertical axis (SVA) was corrected from 191.9 mm preoperatively to 75.9 mm postoperatively (P<0.05) and 78.9 mm at the most recent follow-up (P<0.05). The average correction angles at the osteotomy site were 44.5° postoperatively and 45.0° at the most recent follow-up (P>0.05). Sagittal translation (ST) occurred in 2 patients, and 5 mm was the maximum. There was no neurologic damage. Solid fusion was observed at the most recent follow-up in all patients.

Conclusions

Modified closing-opening wedge osteotomy (mCOWO) is an effective technique for correcting kyphosis in patients with AS.

Intraosseous Malignant Peripheral Nerve Sheath Tumor of 2 Consecutive Lumbar Vertebrae: A Case Report and Literature Review

BACKGROUND

Malignant peripheral nerve sheath tumor (MPNST), which refers to any malignant tumor that originates from peripheral nerve sheath cells, is rarely found in the spine. Primary intraosseous spinal MPNSTs are extremely uncommon; in fact, such an occurrence has been reported in a very limited number of cases hitherto. We report here one case of low-grade intraosseous MPNST in the lumbar vertebrae and review clinical research related to this rare tumor and modus operandi to its treatment.

CASE DESCRIPTION

A 51-year-old man suffering from lower back pain was initially diagnosed with lumbar tuberculosis. The intraoperative histopathologic examination, however, revealed that the occupying lesion was synovial sarcoma when surgeons intended to perform a debridement surgery of what was thought to be tuberculosis. The operation was therefore suspended. Two months later, the patient was referred to our institution. The pathologic sections were reexamined. Its results refuted the earlier thought of being synovial sarcoma, and a final diagnosis of MPNST was made. In addition, preoperative examination revealed that the tumor had advanced rapidly to the adjacent inferior vena cava and pedicle, which ruled out the possibility of performing a total en bloc spondylectomy. Therefore, a marginal resection for 2-level consecutive lumbar vertebrae was performed successfully via an anterior-posterior combined approach. No serious complications were detected at 18-month follow-up.

CONCLUSIONS

Preoperative biopsy is of great importance for the diagnosis of spinal tumors. Marginal resection of a complicated intraosseous spine MPNST via an anterior-posterior combined approach, despite being technically challenging, resulted in good survival and functional outcomes.

Is It Possible to Correct Congenital Spinal Deformity Associated With a Tethered Cord Without Prophylactic Intradural Detethering?

BACKGROUND

Patients who have a congenital spinal deformity with a tethered cord generally are treated with prophylactic intradural detethering before deformity correction. However, the detethering procedure carries substantial risk, and it is not clear whether deformity correction can be performed without detethering.

QUESTIONS/PURPOSES

To determine the (1) correction rate, (2) proportion of patients who experienced complications after surgery, and (3) neurological status after recovery from surgery in a group of patients with congenital spinal deformity and a tethered cord who were treated either with posterior spinal fusion only (PSF), pedicle-subtraction osteotomy (PSO), or a vertebral column resection (VCR), based on an algorithmic approach.

METHODS

Between 2006 and 2016, we treated 50 patients surgically for a congenital spinal deformity and a tethered cord. We defined a congenital spinal deformity as one that was caused by failure of vertebral segmentation, failure of vertebral formation, or both, and we made the diagnosis of a tethered cord based on a conus medullaris lower than L2 level, or a diameter of the filum terminale greater than 2 mm, as shown on magnetic resonance image. Of those, nine patients were lost to followup before the 2-year minimum, leaving 41 for analysis at a mean followup of 47 months (range, 24 to 92 months) in this single-institution retrospective study. The treatment algorithm involved one of three approaches: PSF, PSO, or VCR. A total of 15 patients underwent PSF; we used this approach for patients with moderate curves (Cobb angle < 80°) and intact neurological status both previously and during a bending and traction test. Eleven patients underwent PSO; we performed PSO when patients had neurological symptoms (in daily life or during the traction/bending test) and a magnitude of the curve less than 80°. Finally, 15 patients underwent VCR, which we used in patients with a magnitude of the curve more than 80° and/or flexibility less than 20%, with/without neurological symptoms. No patient in any group underwent intradural detethering. We report on the correction rate, defined as the ratio between the corrected magnitude and preoperative magnitude of a curve at a given postoperative time point (correction rate = 1- (Cobb angle at a given time point/preoperative Cobb angle) x 100%); complications, that is, postoperative/recurrent neurological symptoms, cerebrospinal fluid leakage, infection, blood loss > 5000 mL, as determined by chart review performed by an individual not directly involved in patient care; and a detailed neurological exam, including evaluations of sensory function, extremity muscle strength, pain, gait, physiological reflexes, and pathological signs, both before surgery and at most recent followup, as performed by the surgeon. All neurologically symptomatic patients were evaluated with a neurologic scoring system.

RESULTS

The overall mean ± SD correction rate in this series was 63% ± 14%. It was 70% ± 12% in the PSF group, 64% ± 17% in the PSO group, and 56% ± 12% in the VCR group. Seven patients in those three groups experienced major complications, including blood loss more than 5000 mL, temporary neurological symptoms, cerebrospinal fluid leakage, and infection. The most severe complications included one patient in the VCR group who had temporarily decreased strength in the lower limb, and one patient in the PSO group with temporary numbness in the lower limb. Finally, no patients in PSF group had postoperative neurological complications, and all patients with neurological symptoms in the PSO/VCR group improved to varying degrees. For neurologically symptomatic patients in PSO group (n = 6), the neurological score improved slightly, from 22.5 ± 1.9 preoperatively to 24.2 ± 0.8 at the most recent followup (p = 0.024) with a mean difference of 1.7. For neurologically symptomatic patients in VCR group (n = 10), the neurological score improved slightly from 23.1 ± 1.1 preoperatively to 24.2 ± 0.6 at most recent followup (p = 0.009) with a mean difference of 1.1.

CONCLUSIONS

Congenital spinal deformity with a tethered cord may be treated without prophylactic intradural detethering. In the current series treated according to this treatment algorithm, good correction and neurological improvement were achieved, and few complications occurred. However, such a small series cannot prove the safety of this treatment; for that, larger, multicenter studies are necessary.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Surgical Outcome Comparison of Posterior Vertebral Column Resection with or without Anterior Column Support in Treatment of Yang's Type A Severe Thoracic Spinal Deformity

BACKGROUND

The use of posterior vertebral column resection (PVCR) has extended the treatment of severe spinal deformity. However, the practice guidelines for anterior column support in patients treated by PVCR remain ill defined. The objective of the present study was to compare the clinical and radiographic outcomes of severe thoracic spinal deformity treated by PVCR with and without anterior column support (ACS).

METHODS

We performed a prospective study of 57 patients with severe thoracic deformity (classified as Yang's A type) treated by PVCR with or without anterior column support from January 2010 to April 2015. The patient characteristics, radiographic parameters, intraoperative data, and complications were analyzed to clarify these 2 clinical series.

RESULTS

The sex, age, diagnosis, curve magnitude, and curve type were similar between the PVCR with ACS group (n = 21) and non-ACS group (n = 36) preoperatively. Evaluation of the radiographic parameters, intraoperative data, and complications found no statistically significant intergroup differences, except for the osteotomy distance (non-ACS group, 4.0 cm; ACS group, 5.3 cm; P < 0.001) and shortening distance of the osteotomy gap (non-ACS group, 4.0 cm; ACS group, 3.5 cm; P = 0.005).

CONCLUSIONS

The results of the present study have shown that PVCR without ACS seems to be a safe and effective technique for Yang's A type severe thoracic spinal deformity correction compared with PVCR with ACS. PVCR without ACS requires a relatively smaller osteotomy range and could potentially decrease the risk of implant failure due to bone to bone fusion.

Neuromonitoring in Spinal Deformity Surgery: A Multimodality Approach

STUDY DESIGN

Literature review.

OBJECTIVE

The aim of this study was to provide an overview of the available intraoperative monitoring techniques and the evidence around their efficacy in vertebral column resection.

METHODS

The history of neuromonitoring and evolution of the modalities are reviewed and discussed. The authors' specific surgical techniques and preferred methods are outlined in detail. In addition, the authors' experience and the literature regarding vertebral column resection and surgical mitigation of neurologic alarms are discussed at length.

RESULTS

Risk factors for signal changes have been identified, including preoperative neurologic deficit, severe kyphosis, increased curve magnitude, and significant cord shortening. Even though no evidence-based treatment algorithm exist for signal changes, strategies are discussed that can help prevent alarms and address them appropriately.

CONCLUSION

Through implementation of multimodal intraoperative monitoring techniques, potential neurologic injuries are localized and managed in real time. Intraoperative monitoring is a valuable tool for improving the safety and outcome of spinal deformity surgery.

Vertebral column decancellation in Pott's deformity: use of Surgimap Spine for preoperative surgical planning, retrospective review of 18 patients

Background

In the late stage of Spinal tuberculosis, the bony destruction and vertebral collapse often leads to significant kyphosis, presenting clinically as a painful gibbus deformity, with increased instability, vertebral body translations and increased risk of neurologic involvement. Vertebral column decancellation is thought to be suitable for most patients with severe rigid kyphosis. Surgimap Spine, could offer a pragmatic graphical method for the surgical planning of osteotomies. The aim of this study was to evaluate the efficacy of Vertebral column decancellation planned preoperatively with the computer software-assistance in the patients with Pott’s kyphosis.

Methods

Between May 2012 and May 2015, 18 patients with Pott’s kyphosis underwent the Vertebral column decancellation using Surgimap Spine for preoperative surgical planning. Preoperative and postoperative Konstam’s angle, sagittal vertical angle, lumbar lordosis, thoracic kyphosis, pelvic tilt and pelvic incidence were measured. Visual analog scale and American Spinal Injury Association were documented.

Results

The Konstam’s angles decreased from 88.1° (range, 70–105°) preoperatively to 18.5° (range, 7–31°) (P < 0.01). All patients reached the physiological limits at the final follow-up. The mean VAS score was reduced from preoperative 7.1 (range, 6–8) to 1.8 (range, 1–3, P < 0.01) and the ODI improved from 65.8% (range, 58–74%) to 20.2% (range, 12–38%, P < 0.01). At final follow-up, there was radiographic evidence of solid fusion at the osteotomy site and fixed segments in all patients. Neurological function improved from ASIA scale D to E in 5 patients. The patients were followed up for 30.4 months on average.

Conclusion

Vertebral column decancellation is an effective treatment option for severe Pott’s kyphosis. The surgical planning software Surgimap Spine can be a reliable and helpful tool that provides a simplified method to evaluate and analyze the spino-pelvic parameters and simulate the osteotomy procedure. According to individual character, the appropriate surgery strategy should be selected.

Osteotomies in ankylosing spondylitis: where, how many, and how much?

INTRODUCTION

This article presents the current concepts of correction of spinal deformity in ankylosing spondylitis (AS) patients. Untreated AS can be a debilitating disease. In a few patients, disease progression results in severe spinal deformity affecting not only the thoracolumbar, but also the cervical spine. Surgery for correction in AS patients has a long history. With the advent of modern instrumentation, standardization of surgical and anesthesiologic techniques, surgical safety and corrective results could be improved and experiences from lumbar osteotomies could be transferred to the cervical spine.

METHODS

This article presents the current concepts of correction of spinal deformity in AS patients. In particular, questions regarding the localization and number of osteotomies, the optimal surgical target angle as well as planning and prediction of postoperative alignment are discussed.

RESULTS

Insight into recent technical developments, current challenges with correction and geometric analysis of center of rotation (COR) in cervical 3-column osteotomies (3CO) will be presented.

CONCLUSION

The article should encourage readers to improve surgical correction efficacy and provide a better understanding of correction geometry in 3CO for thoracolumbar and cervical spinal deformities.

Risk factors of instrumentation failure after multilevel total en bloc spondylectomy

INTRODUCTION

Multilevel total en bloc spondylectomy (TES) is required to secure oncologically adequate resection margins. However, no useful information has been reported for spinal reconstruction after multilevel TES. Therefore, this study set out to assess the clinical and radiological outcomes of spinal reconstruction after multilevel TES.

METHODS

Forty-eight patients treated with multilevel TES at our institute were included in the analysis. Reconstruction was achieved with posterior pedicle screw fixation and an anterior titanium mesh cage filled with iliac autograft in all cases. Spinal shortening was performed to increase spinal stability from the reconstruction. Instrumentation failure and radiological findings were evaluated with radiography and computerized tomography (CT).

RESULTS

After excluding one patient whose general condition was deteriorating, radiological evaluations of 47 patients were performed over a period of more than a year. The follow-up time was 17 to 120 months (mean: 70.2 months). Instrumentation failure occurred in one patient (5.9%) after thoracic multilevel TES, in 4 patients (25.0%) after thoracolumbar multilevel TES, and in 3 patients (42.9%) after lumbar multilevel TES. No instrumentation failure was observed in cervicothoracic cases. Cage subsidence (>2 mm) occurred in 30 patients (63.8%). In 22 of them, subsidence appeared on the CT one month after surgery. The risk factors of instrumentation failure included a multilevel TES below the thoracolumbar level and a long span of vertebral resection. There was no instrumentation failure in any of the 11 "disc-to-disc cutting" cases.

CONCLUSIONS

This study identified the risk factors of instrumentation failure after multilevel TES. There is a high risk of instrumentation failure in cases of long vertebral resection below the thoracolumbar level. On the other hand, our reconstruction method can be successful for multilevel TES above the thoracic level.

Proper Responding Strategies to Neuromonitoring Alerts During Correction Step in Posterior Vertebral Column Resection Patients With Severe Rigid Deformities Can Reduce Postoperative Neurologic Deficits

MINI: The neurological risks in posterior vertebral column resection can be resulted from spinal cord tension changes following correction maneuvers being performed. On the basis of intraoperative neuromonitoring alerts, to timely identify them as well to act prompt surgical interventions can decrease the risks.

STUDY DESIGN

Retrospective study.

OBJECTIVE

To analyze the intraoperative neuromonitoring (IOM) changes in posterior vertebral column resection (PVCR) for severe rigid deformity patients, and describe our stepwise responding strategies.

SUMMARY OF BACKGROUND DATA

Obvious neurological deficit risk accompanied with PVCR correction has been emphasized repeatedly.

METHODS

The records of 46 patients who underwent PVCR achieved IOM were reviewed. IOM alerts triggered responding protocols: (1) exchange the convex corrective rod to concave stabilizing rod, (2) appropriate compression for spinal shortening, (3) reversed in situ rod bending, (4) translation technique and unisegmental derotation, (5) adjacent segmental resection.

RESULTS

The overall scoliotic correction rate was 65.4% (from 112 ± 28.6 to 39 ± 13.4) and segmental kyphotic correction rate was 64.2% (from 101 ± 37.3 to 36 ± 19.2). During correction step, somatosensory-evoked potential warning (3) and somatosensory-evoked potential/transcranial motor-evoked potential warning (8) were detected in 11 patients (23.9%). Probable cause identification including rule out IOM technical factors, residual impingement, and if there was unstable spinal column (1), spinal cord excessive tension on concave side (3), and the excessive opposite spinal displacement between two aspects of resected area (7). After rod change (1), compression (2), bending (3), derotation (3), and adjacent resection (2), all IOM changes went to under warning criteria. All 11 patients revealed neurologically intact postoperatively. There was no difference of correction rate between IOMs alert or not. However, adult, extremely severe or sharp angular curves tend to be more common in IOM alert patients.

CONCLUSION

As three-dimensional spinal column divided and relinked in PVCR, and the correction maneuvers were restricted on single dimension, inevitably resulted in spinal cord tension changes and spinal column opposite displacement. To timely identify them, prompt interventions should be performed, and even enlarge the resected area to reduce the abrupt turning tendency of the spinal cord.

LEVEL OF EVIDENCE

5.