Expert consensus for PVCR in severe, rigid and angular spinal deformity treatment: The Kunming consensus

Posterior vertebral column resection: Exploring practical uses in clinical settings

Background

The purpose of this study was to present our experience in patients who had been treated with posterior vertebral column resection (PVCR) for various spinal deformities.

Methods

Thirty-seven patients who performed PVCR between 2015 and 2018 were evaluated retrospectively. The mean follow-up period was 24 months (range: 12-50 months). The demographic data of the patients, mean blood loss, amount of blood replacement, duration of operation, intensive care and hospitalization period, PVCR level, instrumentation level, amount of preoperative curvature, amount of postoperative curvature improvement, preoperative and postoperative neurological status, and complications were examined. Angular measurements were performed on X-ray.

Results

The mean age of the patients was 37.5 years (range: 3-80 years). PVCR was applied to patients due to different pathologies (congenital, tumor metastasis, posttraumatic kyphosis, revision scoliosis, and infection). The mean operation time was 445.5 min (260-720) with an average blood loss of 1903 ml (400-7000 ml). It was observed that the average local kyphosis angle decreased from 67.65° to 7.42° in 26 patients who were operated for advanced deformity (P < 0.001). When these values were compared in all 34 patients, the preoperative angle value decreased from 55.1° to 3.5° (P < 0.001) and decreased from 70° to 0° in 13 congenital kyphosis patients.

Conclusion

PVCR is an effective method for correcting severe spinal deformities and can be used to correct curvature in different patient groups.

Level of Evidence

Level 3.

Sequential correction using satellite rod for the treatment of severe rigid spinal deformity: a retrospective study of 19 cases

OBJECTIVES

The purpose of this study was to evaluate the effectiveness of sequential correction using satellite rod in patients with severe rigid spinal deformity undergoing posterior-only PVCR.

METHODS

19 patients with severe rigid spinal deformity who underwent PVCR at our center from January 2014 to December 2019 were reviewed. Radiographic measurements, including major coronal Cobb angle, kyphotic curve angle, coronal and sagittal balance were measured. Clinical results were noted, including the SRS-22 questionnaire, the Oswestry Disability Index score, and complications.

RESULTS

Total 19 patients were followed at least 2 years. The mean coronal Cobb angle decreased from 122.7° ± 13.17° to 57.89° ± 8.65° postoperatively, and to 58.42° ± 8.98° at final follow-up. Correction rate is 52.8%. The kyphotic curve angle improved from 102.2° ± 17.05° preoperatively to 39.68° ± 13.67° postoperatively, and to 37.74° ± 12.14° at final follow-up. Correction rate is 61.2%. Compared to preoperative results, apex vertebral translation, ODI and SRS-22 were significantly improved at the final follow-up.

CONCLUSIONS

For patients with severe rigid spinal deformities, sequential correction with an auxiliary satellite rod can effectively reduce surgical difficulty and improve correction rate.

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.

Is There a Correlation Between Cobb Angle and Pulmonary Function Tests at 2-year Follow-up in Patients With Severe Spinal Deformity Treated by Posterior Vertebral Column Resection?

STUDY DESIGN

A retrospective study.

OBJECTIVE

The aim was to evaluate the relationships of Cobb angle and pulmonary function tests (PFTs) changes in severe spinal deformity and underwent posterior vertebral column resection (PVCR).

SUMMARY OF BACKGROUND DATA

No previous study focused on the correlation of deformity correction and PFTs changes in patients with cobb angle >90 degrees.

METHODS

PFTs values [forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and percent-predicted values FVC%, FEV1%] were evaluated preoperative and at 2 years after PVCR. FVC% <80% were defined as restrictive ventilation dysfunction (RVD), the severity of RVD were divided into mild (FEV1% ≥70%), moderate (70% > FEV1% ≥50%) and severe (FEV1% <50%). The relationships among PFTs values improvements and all possible impact factors (mainly correction cobb angle) collected in this study were analyzed. PFTs data were compared among the 3 RVD subgroups (mild vs. moderate vs. severe) and between residual >30 versus <30 degrees.

RESULTS

A total of 53 cases (28 male/25 female, mean ages 18.9 Y) underwent PVCR in one center from 2004 to 2016 were enrolled cobb angle. When 2 years after PVCR, average PFTs values showed significant improvements. PFTs values changes showed no correlation with correction rate and correction angle. The only significant impact factor in this study for FVC, FVC%, FEV1 improvements was preoperative FVC% and the only impact factor for FEV1% improvement was preoperative FEV1%, the relationships were negative. In accordance with the regression analysis, PFTs values improvements among the 3 RVD subgroups from high to low was severe>moderate>mild. However, patients with residual cobb angle <30 degrees had less PFTs values improvements than patients with residual cobb angle >30 degrees.

CONCLUSIONS

Two years after PVCR, PFTs values were significantly improved. There is no linear correlation between cobb angle change and PFTs values improvements. Lower preoperative FVC% and FEV1% indicate more PFTs values improvements at 2 years post-PVCR.

LEVEL OF EVIDENCE

Level III.

Osteotomies for the Treatment of Adult Spinal Deformities: A Critical Analysis Review

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Spinal osteotomies are powerful deformity correction techniques that may be associated with serious complications.

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The anatomical spinal osteotomy classification system proposes 6 grades of resection corresponding to different anatomic bone, disc, facet, and ligament interventions.

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Surgeons should be aware of the nuances of 3-column osteotomies with regard to spinal level selection, construct composition, and posterior column reconstruction and closure techniques.

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There is a global tendency toward avoiding 3-column osteotomies as much as possible because of the growing evidence regarding the effectiveness of posterior column osteotomies and halo-gravity traction.

Development and initial validation of classification for severe spinal deformity based on X-ray features

PURPOSE

To develop a clinically feasible classification for severe spinal deformity based on X-ray features.

METHODS

A total of 223 consecutive severe spinal deformity cases who underwent corrective operation were enrolled from 2004 to 2015 retrospectively. Based on X-ray features, a novel classification was developed containing three components: curve types, curve angle and apex location. There were five curve types as follows: single scoliosis (SS), kyphoscoliosis (KS), angular deformity (AD), long curve (LC), and double curves (DC). Curve angle subsection on coronal and sagittal planes including A:90-109, B:110-129, C:130-149, D: > 150. Apex location means the exact level of apex located. Reliability of the classification was tested.

RESULTS

The kappa values for inter-observer and intra-observer reliability of the curve types, curve angle, and apex level were larger than 0.80. X-ray classification for overall patients with severe spinal deformity showed that there were 101 SS cases, 47 KS, 46 AD, 19 LC and 10 DC. For the curve angle, there were grade A 123 cases, B 43, C 18, D 15 on coronal plane and grade A 38, B 17, C 16, and D 19 on sagittal plane. Apex location showed there were 27 patients at T7 or upper levels, 31 on T8, 58 on T9, 45 on T10, 18 on T11, and 44 at T12 or lower levels.

CONCLUSION

A novel classification for severe spinal deformity was described based on X-ray morphology. A high value for inter-observer and intra-observer reliability was shown. Each subgroup has its particular influence on decision-making and prognostic prediction.

Outcome of Posterior-Only Approach for Severe Rigid Scoliosis: A Retrospective Report

BACKGROUND

The management of severe scoliosis may lead to significant complications, and adequate mobilization is a key step to achieve maximal correction, usually requiring extensive approaches. There is still no consensus on the management of these severe and rigid curves. In this study we evaluated the clinical and radiologic outcome of a posterior-only approach with multilevel asymmetric Ponte osteotomy with a minimum of 2 years' follow-up.

METHODS

In this retrospective study, 23 patients with severe and rigid adolescent idiopathic scoliosis who underwent surgery with a single-staged posterior-only approach were included. The surgical procedures in these patients were excision of posterior ligaments and spinous process, partial laminectomy in caudal part of lamina, excision of the ligamentum flavum, facetectomies, and multilevel asymmetric posterior column osteotomies (Ponte) followed by instrumented fusion. Clinical records-including demographic data; operating time; hospitalization time; blood loss; number of segments instrumented, fused, and osteotomized; functional improvement; follow-up duration; and complications-were recorded.

RESULTS

The mean preoperative Cobb angle of major curve in coronal plan was 97.5° (range, 82°-131°) with the mean flexibility of 21.4° (range, 10°-25°) on bending radiography. The mean immediate postoperative Cobb angle of major curve was 34.8° (range, 17°-61°), showing a 64.2% correction. The mean preoperative coronal and sagittal imbalances of 3.8 and 4.2 cm were improved to 1.0 and 1.3 cm at postoperative measurements, respectively. A mean of 6.1 (range, 5-9) vertebral segments were osteotomized. We experienced no major complications.

CONCLUSIONS

We found that a posterior-only procedure in patients with severe and rigid adolescent idiopathic scoliosis could provide correction rate, coronal and sagittal balance, and clinical outcomes comparable with other procedures. Using this technique can eliminate the need for the anterior release, with the associated complications related to anterior surgery, in the treatment of severe rigid scoliosis.

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.