Vertebral Column Resection Procedures Research Articles

Posterior Corrective Surgery for Type II Congenital Kyphosis: SRS-Schwab Grade 4 Osteotomy or Vertebral Column Resection?

Surgical decision-making for congenital kyphosis (CK) with failure of anterior segmentation (type II) has been contradictory regarding the trade-off between the pursuit of correction rate and the inherent risk of the osteotomy procedure. This study was designed to compare the clinical and radiographic measurement in type II CK underwent SRS-Schwab Grade 4 osteotomy and vertebral column resection (VCR), the most-adapted osteotomy techniques for CK, and to propose the strategy to select between the two procedures. This retrospective observational comparative study evaluated surgical outcomes in type II CK patients underwent VCR or SRS-Schwab Grade 4 osteotomy at our institution between January 2015 and January 2020. Patients operated with VCR and SRS-Schwab Grade 4 osteotomy were allocated to Group 1 and Group 2 respectively. Radiographic parameters and SRS-22 quality of life metrics were assessed at pre-operation, post-operation, and during follow-up visits for both groups, allowing for a comprehensive comparison of surgical outcomes. Thirty-one patients (19 patients in Group 1 and 12 patients in Group 2) aged 16.3 ± 10.4 years were recruited. Correction of segmental kyphosis was similar between groups (51.1 ± 17.6° in Group 1 and 48.4 ± 19.8° in Group 2, p = 0.694). Group 1 had significantly longer operation time (365.9 ± 81.2 vs 221.4 ± 78.9, p < 0.001) and more estimated blood loss (975.2 ± 275.8 ml vs 725.9 ± 204.3 mL, p = 0.011). Alert event of intraoperative sensory and motor evoked potential (SEP and MEP) monitoring was observed in 1 patient of Group 2. Both groups had 1 transient post operative neurological deficit respectively. SRS-Schwab Grade 4 osteotomy was suitable for kyphotic mass when its apex is the upper unsegmented vertebrae or the neighboring disc, or when the apical vertebrae with an anterior/posterior (A/P) height ratio of vertebral body higher than 1/3. VCR is suitable when the apex is located within the unsegmented mass with its A/P height ratio lower than 1/3. Proper selection of VCR and SRS-Schwab Grade 4 osteotomy according to our strategy, could provide satisfying radiographic and clinical outcomes in type II CK patients during a minimum of 2 years follow-up. Patients undergoing VCR procedure might have longer operation time, more blood loss and higher incidence of peri- and post-operative complications.

A novel Hinge-Link correction system for vertebral column resection: a pilot study in a porcine model.

To introduce a novel Hinge-Link (HL) correction system for vertebral column resection (VCR) in the most severe scoliosis and surgically assess the device in a porcine scoliosis model. The HL was introduced and described how it works on a reproduced three-dimensional spine model of severe scoliosis. A right thoracic scoliosis was surgically created in five 4-month-old pigs. Two weeks later, the VCR was performed to correct the deformity using the HL to test its feasibility and neurological safety in the pig scoliosis model. The surgically created right thoracic scoliosis averaged 32° ± 9.3 prior to the VCR. All animals tolerated the VCR procedure awakening neurologically intact and ambulated for 24h. The HL takes advantage of the ability to provide three-dimensional correction of the deformity and excellent control of the spine segments to prevent damage to the spinal cord in the VCR procedure. The mean correction of the scoliosis was 94% correcting to 1.8° ± 0.8. At sacrifice, the pathological anatomy of the neural axis demonstrated no vertebral subluxation and no dural impingement in any animal. The HL was feasible and neurologically safe for the VCR procedure in the pig scoliosis model. It can provide significant correction of the spinal deformity with appropriate mild shortening at the resected levels and overall lengthening without neurologic deficits. The rigid control of the spine segments provided by this device should allow for improved correction with decreased neurologic deficits and potentially shorter surgical time.

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

To analyze the incidence and risk factors of intraoperative neurophysiological monitoring (IONM) alerts in patients undergoing three-column osteotomy. 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. 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 χ2 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. 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.

318. Severe pediatric deformity surgery had frequent IOM alerts but a low rate of permanent deficits at two years

BACKGROUND CONTEXT Surgical treatment of severe pediatric spinal deformity is challenging and can have a high risk of neurologic injury. We investigated the incidence of intraoperative monitoring (IOM) alerts during surgery and the development of new neurologic deficits in a prospective multicenter cohort. PURPOSE The purpose of this study was to evaluate the frequency of IOM alerts during surgery for severe pediatric deformity and determine the incidence of new permanent deficits at 2 years postoperative. STUDY DESIGN/SETTING Prospective observational multicenter cohort of severe pediatric deformity patients treated surgically for minimum curves of 100° or planned vertebral column resection (VCR). PATIENT SAMPLE Patients with a minimum spinal deformity curve of 100° or who were scheduled for a VCR procedure were prospectively enrolled at 17 sites. OUTCOME MEASURES IOM alerts, radiographic parameters, surgical procedures, neurological status. METHODS Patients with severe spinal deformity with minimum curves of 100°; or planned VCR were followed for a minimum 2 years postoperative. We studied x-ray parameters, IOM changes, postop deficits and recovery at minimum 2 years. RESULTS A total of 228 of the 312 patients enrolled had a minimum two years follow-up (QOLs and x-rays). Of these, 110 patients had a VCR and 1 a PSO. Two hundred twelve had a post-only approach and 16 a combined anterior/posterior. Two hundred twenty-eight patients had a total of 272 procedures including all stages; IOM alerts occurred in 102/272 procedures (38%). IOM alerts occurred in 98 pts (43%), with a total of 147 IOM alerts. An analysis was completed between a VCR, ant/post, coronal deformity angular ratio (C–DAR), the sagittal deformity angular ratio (S–DAR), and any IOM alert, SSEP, TCeMEP or both. Only S-DAR was predictive for any IOM alert (p CONCLUSIONS Pediatric patients with severe deformity had a 43% incidence of IOM alerts but after addressing the alerts intraop, only 2 patients had new deficits at 2 years. Of the 19 patients with preoperative neurologic deficit, 16 patients improved or recovered. Neural monitoring should be mandatory in these cases. Sagittal DAR is associated with IOM alerts and new neurologic deficits. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Intraoperative neuromonitoring alerts in a pediatric deformity center.

OBJECTIVE Intraoperative neuromonitoring (IONM) involves the use of somatosensory evoked potentials (SSEPs) and transcranial electric motor evoked potentials (TceMEPs). In this retrospective study the authors examined the sensitivity and specificity of both SSEPs and TceMEPs during pediatric spinal deformity surgeries. METHODS The authors performed a retrospective quantitative analysis of data obtained in 806 patients (197 males and 609 females) treated from December 2011 until October 2015. All patients were diagnosed with scoliosis that was classified as one of the following: adolescent idiopathic scoliosis (AIS) (38%), congenital scoliosis (22%), or syndromic scoliosis (40%). Also, 53 patients underwent vertebral column resection (VCR). All surgeries were monitored by high-level neuromonitoring specialists and were performed with total intravenous anesthesia. Alerts were described as a decrease in amplitude by 50% or greater (bilateral or unilateral) in SSEPs, TceMEPs, or both. RESULTS True-positive alerts for TceMEPs were observed in 60 of the 806 patients (7.4%). True-positive alerts for SSEPs were observed in 7 of the 806 patients (0.9%). In contrast, there were no false-positive or false-negative outcomes. Only 1 case (0.1%) was reported with a permanent postoperative deficit. No reported false negatives or false positives were observed, and thus sensitivity was 100% and specificity was 93%-100% for TceMEPs. The rate of sensitivity was 13.2% and the rate of specificity was 100% for SSEPs. The breakdown of total alert was as follows: 6.6% in AIS cases, 24.5% in congenital scoliosis cases, and 10.2% in syndromic scoliosis cases. Neurological injury rates were significantly lower than in previous studies, as there were 0% for AIS cases (p = 0.12), 0.6% for congenital scoliosis cases (p = 0.17), and 0% for syndromic scoliosis cases (p = 0.07). One injury in a patient with congenital scoliosis occurred during a VCR procedure, which brought the injury rate to 1.9% (p < 0.005). IONM alerts occurred during 34% of rod/correction cases, 25% of thoracic screw placements, 20% of the osteotomies, 17% of the resections, 3% of the cage insertions, and 2% of the sublaminar wiring procedures. CONCLUSIONS The authors hypothesize that the results of this study will support the necessity, as a standard of care, of multimodality neuromonitoring during high-risk pediatric spinal deformity surgery because of the decrease in postoperative deficits. Their data suggest that the TceMEPs are more sensitive than SSEPs, but when used in combination, they offer the patient a level of safety that would otherwise not exist. Last, these findings support the notion that better outcomes are achieved with high-level IONM professionals.

Frequent neuromonitoring loss during the completion of vertebral column resections in severe spinal deformity surgery

Background ContextIntraoperative monitoring (IOM) is an essential method for preventing postoperative spinal deficits during posterior vertebral column resection (VCR) surgery for treatment of severe spine deformities, but the IOM features directing at VCR procedures are rarely reported and need to be further clarified. PurposeTo evaluate an important surgical point that will lead to the IOM loss frequently, and then remind the surgeons to pay close attention to impending monitoring changes during posterior VCR surgery. Study Design/SettingRetrospective study. Patient SampleA total of 77 patients with severe spine deformities who underwent posterior VCR and deformity correction surgeries from January 2012 to May 2015 are retrospectively analyzed in our spine center. Outcome MeasuresIOM (motor-evoked potentials [MEP] and somatosensory-evoked potentials) was used for intraoperative spinal function assessment. MethodsPatients were divided into 2 groups according to their preoperative spinal function, including 27 patients with preoperative spinal deficits and 50 patients with spinal normal. And the IOM data during surgery, especially among VCR procedures, were mainly analyzed in the present study. ResultsWith the VCR procedure almost complete, most patients showed varying degrees of IOM loss that included 37 cases showing obvious IOM degenerations and 21 cases showing significant IOM loss with alerts immediately. Moreover, the patients with preoperative spinal deficits have more significant decreasing percentage in MEP amplitude (81% vs. 68%, p<.05) than those patients without. ConclusionsWith the VCR procedure almost complete, surgeons must pay closely attention to the IOM signals and should be ready to take corresponding surgical measures to deal with the impeding monitoring loss.

The clinical analysis of instrumentation failure after corrective surgery for thoracolumbar focal kyphosis

To analyze the etiology of instrumentation failure after corrective surgery for thoracolumbar focal kyphosis, and make suggestion for treatment. Retrospective study for 8 patients with thoracolumbar focal kyphosis who underwent surgical treatment and suffered instrumentation failure from June 2005 to December 2011 was made. The surgical procedures included pedicle subtraction osteotomy (PSO), anterior opening-posterior closing osteotomy and correction (AOPC), and posterior vertebral column resection (VCR). The reasons of instrumentation failure were analyzed and revision surgeries were performed. The incidence of instrumentation failure was 6.3%. The average occurrence time was 22.5 months after surgery. Except one had failure in 3 months after surgery, all cases happened after 1 year. In this series, there were 5 cases with post-tuberculosis, 2 cases with post-traumatic kyphosis and 1 case with congenital kyphosis. For the surgical procedure, 7 cases underwent VCR and 1 case AOPC. After the instrumentation failure, all cases had back pain, and 3 of them had combined neurological symptoms. The reasons or risk factors of instrumentation failure included non-fusion of bone graft, VCR procedure, sink of the titanium mesh, insufficiency of anchor sites, and more severe kyphosis. All the 8 cases were treated with revision surgery and got good results. The instrumentation failure of thoracolumbar focal kyphosis is relatively late occurred, and can develop with various reasons. Positive revision surgery is suggested for the instrumentation failure, and good results can be expected.

Intraoperative neurophysiologic monitoring during spinal osteotomies

The Smith-Petersen osteotomy/Ponte osteotomy, pedicle subtraction osteotomy, cervical extension osteotomy, and vertebral column resection procedures have a high risk of neurologic complications because of blood loss, high correction forces, and numerous opportunities for direct spinal cord injury. Intraoperative neurophysiologic monitoring with a combination of motor evoked potentials, somatosensory evoked potentials, and electromyography permits real-time analysis of possible nerve irritation/damage. Management, including stabilizing mean arterial pressure, decreasing or reversing the corrected kyphotic deformity, and ordering a Stagnara wake-up test to confirm the neurologic status can provide the immediate response necessary to minimize neurologic complications.

Mini-Open Anterior Retroperitoneal Lumbar Interbody Fusion: Oblique Lateral Interbody Fusion for Degenerated Lumbar Spinal Kyphoscoliosis.

Study DesignProspective case series.PurposeTo examine the clinical efficacy of mini-open anterior retroperitoneal lumbar interbody fusion: oblique lateral interbody fusion (OLIF) for degenerated lumbar spinal kyphoscoliosis.Overview of LiteratureThe existing surgical procedures for the treatment of spinal kyphotic deformity, including Smith-Petersen osteotomy, pedicle subtraction osteotomy, and vertebral column resection procedures, are invasive in nature. Extreme lateral interbody fusion to provide less invasive treatment of the deformity has been reported, but complications including spinal nerve and psoas muscle injury have been noted. In the current study, we examined the clinical efficacy and complications of OLIF for degenerated lumbar spinal kyphoscoliosis.MethodsTwelve patients with degenerated lumbar spinal kyphoscoliosis were examined. All patients underwent OLIF surgery (using a cage and bone graft from the iliac crest) with open pedicle screws or percutaneous pedicle screws, without real-time monitoring by electromyography. Visual analog scale score and Oswestry disability index were evaluated before and 12 months after surgery, and fusion rate at OLIF cage, correction of the deformity, total blood loss, and surgical complications were also evaluated.ResultsPain scores significantly improved after surgery (p<0.05). Fusion rate was found to be 90%, balance parameters also improved after surgery (p<0.05), and average total blood loss was less than 350 mL. There was no spinal nerve, major vessel, peritoneal, or urinary injury, or breakage of instrumentation.ConclusionsOLIF surgery for degenerated lumbar spinal kyphoscoliosis is less invasive than other procedures and good surgical results were produced without major complications.

The posterior surgical treatment for focal kyphosis in upper-middle thoracic spine.

To analyze the clinical characteristics of focal kyphosis in upper thoracic spine, and observe the outcome of the posterior corrective surgical procedures. Thirteen patients of focal kyphosis were treated with posterior surgical procedures in our medical center. The kyphosis apex was above T6 in all cases. The surgical procedures performed in this study included pedicle subtraction osteotomy (PSO) in six cases and vertebral column resection (VCR) in seven cases. For each case, the kyphosis angle, curvature of lower thoracic spine, lumbar lordosis angle, cervical lordosis angle, pelvic parameters, and the sagittal plane balance of the spine were compared before and after surgery. Neurological function change was assessed based on Frankel grading system and oswestry disability index (ODI). The average follow-up time of this study was 28.3 months. The average kyphosis angle was reduced from 73.5º before surgery to 32.7º immediately after surgery, and remained at 33.5º at follow-up. The average ODI improved from 22.5 before surgery to 15.5 at follow-up. The neurological function improved after surgery in eight cases. There were two cases of transient neurological deficiency in the lower extremities after VCR procedure, who eventually recovered under postoperative care. One case had recurrent kyphosis due to implant failure after VCR procedure, and recovered after the revision surgery. Although high risk needs to be warned, the corrective surgery for focal kyphosis in upper thoracic spine still can achieve satisfactory results. Given the comparative surgical results yet less complications, PSO seems to be a preferable procedure over VCR for kyphosis at this region.

Complications After 147 Consecutive Vertebral Column Resections for Severe Pediatric Spinal Deformity

Retrospective multicenter review. Determine the definition, indications, results, and outcomes, focusing on complications of vertebral column resection (VCR) for severe pediatric spinal deformity. The strict definition of the VCR procedure, indications, results, outcomes, and the numerous, potentially serious complications are unknown or controversial, and a large multicenter review has never been performed. A total of 147 patients treated by 7 pediatric spinal deformity surgeons were reviewed-seventy-four females and 73 males, with an average age of 13.7 years, an average of 1.6 (range, 1-5) vertebrae resected, and an average follow-up of 17 months (range, 0.5-64 mo). The strict definition of VCR used was a "3-column circumferential vertebral osteotomy creating a segmental defect with sufficient instability to require provisional instrumentation." Indications for a VCR were divided into 5 diagnostic categories: kyphoscoliosis (n = 52), severe scoliosis (n = 37), congenital deformity (n = 28), global kyphosis (n = 17), and angular kyphosis (n = 13). Eighty-four primary and 63 revision patients with 174 operative procedures, 127 posterior-only (17 staged), and 20 patients combined anterior-posterior (10 staged) were reviewed. Average preoperative upright, flexibility, and postoperative Cobb measures (% correction or average kyphosis decrease) were kyphoscoliosis: 91°, 65°, 44° (51% coronal), 104°, 81°, and 47° (decrease, 57° sagittal); severe scoliosis: 104°, 78°, and 33° (67%); congenital deformity: 47°, 38°, 22° (46% coronal), 56°, 48°, and 32° (decrease, 24° sagittal); global kyphosis: 101°, 79°, and 47° (decrease, 54°); and angular kyphosis: 88°, 90°, and 38° (decrease, 50°), respectively. Operative time averaged 545 minutes (range, 204-1355 min) and estimated blood loss averaged 1610 mL (range, 50-8244 mL) for an average 65% blood volume loss (range, 6%-316%). Eighty-six patients (59%) developed a complication, 39 patients (27%) having an intraoperative neurological event (spinal cord monitoring change or failed wake-up test); however, no patient had complete permanent paraplegia. A total of 147 consecutive pediatric VCRs performed by 7 surgeons demonstrated excellent radiographical correction. However, these complex reconstructions were associated with a 59% complication rate, thus emphasizing the challenging nature of these patients and procedures.