Using percutaneous parapedicle screw vertebroplasty to treat transpedicle screw loosening.

BACKGROUND: Pedicle screw loosening (PSL) is a postsurgical complication of spinal fusion surgery that can result in morbidity. The aim of this study was to evaluate the efficacy and safety of percutaneous parapedicle screw vertebroplasty (PPSV) for pain reduction and motility improvement in patients with PSL. METHODS: The postsurgical solid inter-body fusion with inter-body bone mass formation of 32 patients who underwent lumbar-sacrum spinal fusion surgery was confirmed with plain films and CT scans. Each patient had one or two screws with symptomatic PSL and was treated with PPSV. All the patients were then followed up for 12 to 24 months. The visual analog scale (VAS) and Roland-Morris Disability Questionnaire (RMDQ) were used to evaluate each patient before the operation, after the operation, and during the follow-up period. RESULTS: A total of 32 patients with a total of 47 screws with PSL were treated with PPSV and experienced different results in terms of pain reduction (with the mean VAS score dropping from 7.97 ± 0.74 to 2.34 ± 1.59, p < 0.001) and motility improvement (with the mean RMDQ score dropping from 16.75 ± 1.84 to 7.21 ± 4.08, p < 0.001). The motility improvement was significantly correlated with pain reduction (r = 0.42, p = 0.018), with the mean follow-up period being 19.3 ± 6.2 months (range: 8-36 months). However, five patients who experienced moderate improvements had eventually received a revision operation after undergoing PPSV. CONCLUSION: The PPSV procedure is effective and safe for the reduction of pain and improvement of life quality in patients with PSL. It can thus be considered as a possible option for the revision of spinal fusion surgery.

Broader curve criteria for selective thoracic fusion.

STUDY DESIGN: Retrospective radiographic review. OBJECTIVE: To evaluate the outcome of selective thoracic fusion (STF) by using cantilever bending technique (CBT) and the direct vertebral rotation (DVR) technique for major thoracic-compensatory lumbar (MTCL) curves selected by new curve criteria, which are broader than Lenke curve criteria for STF. SUMMARY OF BACKGROUND DATA: Surgical treatment of MTCL curves aims to maximize the number of MTCL curves that can be treated with STF and optimize instrumented thoracic and spontaneous lumbar correction. Comparing current guidelines for STF shows that the surgical technique utilized for STF may affect the curve criteria for MTCL curves for successful STF and thoracic and lumbar correction. METHODS: Seventy-eight consecutive idiopathic scoliosis patients with major thoracic-compensatory "C" modifier lumbar curves who met the following three criteria: (1) main thoracic curve (MT) to compensatory lumbar curve (CL) ratios of Cobb magnitude and apical vertebral translation (AVT) greater than one; (2) MT/CL ratio of flexibility less than one; (3) Cobb magnitude of lumbar curve less than 35° on side bending, were treated with STF by using CBT and DVR. Radiographs were analyzed before surgery, immediately after surgery, and at the most recent follow-up (range, 2-5 years). RESULTS: All 78 MTCL curves were successfully treated with STF by using CBT and DVR. A mean 61% thoracic correction was matched by 55% lumbar correction at the most recent follow-up. Spontaneous correction of lumbar AVT occurred in all patients. Global coronal imbalance was common before surgery (mean, 14 mm) and remained so after surgery (mean, 12 mm). There were 49 MTCL curves that did not meet Lenke curve criteria for STF. All were successfully treated with STF by using CBT and DVR. Among these 49 MTCL curves, there were 14 Lenke 1C and 18 Lenke 2C curves with one or two, or all of MT/CL ratios of Cobb magnitude, AVT, and apical vertebral rotation of 1.2 or less, and 6 Lenke 3C and 11 Lenke 4C curves with the Cobb magnitude of residual lumbar curve on side bending between 25° and 35°. CONCLUSION: CBT and DVR can broaden the current curve criteria of MTCL curves for STF to have more MTCL curves treatable with STF and optimize instrumented thoracic and spontaneous lumbar correction. A more effective surgical technique can not only improve instrumented thoracic and spontaneous lumbar correction but also can broaden the MTCL curve criteria for STF to have more MTCL curves treatable with STF.

Quality control of reconstructed sagittal balance for sagittal imbalance.

STUDY DESIGN: Prospective radiographic study. OBJECTIVE: To investigate the feasibility of controlling quality of reconstructed sagittal balance for sagittal imbalance. SUMMARY OF BACKGROUND DATA: Patients with sagittal imbalance cannot walk or stand erect without overwork of musculature because of compromised biomechanical advantage. The result is muscle fatigue and activity-related pain. During reconstructive surgery, restoration of optimal sagittal balance is crucial for obtaining satisfactory clinical results. However, there is no way to control quality of reconstructed sagittal balance before or during surgery. METHODS: A method was developed to determine the lumbosacral curve in a way that theoretically would bring sagittal balance to an ideal state by calculation and simulation for each patient before surgery and then template rods of the curve and a blueprint were made accordingly for operative procedures. Ninety-four consecutive patients with sagittal imbalance due to lumbar kyphosis were treated for intractable pain and then followed up for a mean of 4.3 years. Radiographs were analyzed before surgery, 2 months after surgery, and at most recent follow-up. RESULTS: The mean estimated values of L1-S1 lordosis, sacral inclination angle, sacrofemoral distance, and distribution of L1-S1 lordosis at the closing-opening wedge osteotomy site and L4-S1 segments were 30.8°, 24.6°, 0 mm, 16.1% (-5°), and 62% (-19°), respectively. The mean reconstructed values were 41.1°, 23.3°, 3.9 mm, 41% (-17°), and 46% (-19°), respectively. There were significant differences between estimated and reconstructed values of L1-S1 lordosis and the percentage of distributions; however, there was no significant difference between the estimated and reconstructed magnitude of L4-S1 lordosis, sacral inclination angle, and sacrofemoral distance. A properly oriented pelvis can be brought nearly directly above the hip axis. The mean sagittal global balance, represented by the distance between the vertical line through the hip axis and sacral promontory, improved from 61.4 mm before surgery to 3.9 mm 2 months after surgery, and 1.3 mm at final follow-up. Normal sagittal global balance was reconstructed and maintained. The mean sagittal spinal balance measured as the horizontal distance between the C7 sagittal plumb line and the posterior superior corner of S1 improved from 97.4 mm before surgery to 11 mm 2 months after surgery. However, there was significant loss of sagittal spinal balance to 25.4 mm at the fi nal visit. Normal sagittal spinal balance was reconstructed and appeared to be maintained. The magnitude of T1-T12 kyphosis compensated from 13° before surgery to 25.2° 2 months after surgery and 34.5° at fi nal follow-up. CONCLUSIONS: Quality control of the reconstructed sagittal balance for sagittal imbalance is possible. Correctly orienting the pelvis, reconstructed by the restoration of enough L1-S1 lordosis with adequate distribution at L4-S1 segments, is a matter of critical importance for optimizing reconstructed sagittal balance. The correctly oriented pelvis can be determined before surgery. Preventing junctional fracture and persistent rehabilitation of surgically injured lumbar extensor musculature are crucial for maintaining the reconstructed sagittal balance.

Closing-opening wedge osteotomy for the treatment of sagittal imbalance.

STUDY DESIGN: Closing-opening wedge osteotomy (COWO) had been performed by the senior author (K.C.) since 1998. A study had been conducted to evaluate the efficacy of COWO since 2000. OBJECTIVE: Assess COWO for sagittal imbalance requiring more than 35 degrees lordotic correction at the level of osteotomy. SUMMARY OF BACKGROUND DATA: Correction of sagittal imbalance commonly uses pedicle subtraction osteotomy or closing wedge osteotomy (CWO). Anatomic limitation of 1 vertebral body restricts CWO to approximately 35 degrees of lordosis at the osteotomized vertebra. Further movement often requires over 1 CWO to obtain adequate correction, but can also be achieved using COWO at a single level by fracturing the anterior vertebral cortex. The efficacy of COWO for the treatment of sagittal imbalance is unclear. METHODS: Eighty-three consecutive patients treated for sagittal imbalance with lumbar COWO with a minimum follow-up of 2 years were analyzed. Radiographic analysis included assessment of thoracic kyphosis, lumbar lordosis, lordosis through COWO site, sagittal translation at the site of osteotomy, and sagittal balance. Outcomes analysis used the Scoliosis Research Society questionnaire. Complications and radiographic findings were analyzed. RESULTS: The average increase in lordosis and improved sagittal balance were 81.9 degrees and 17.1 cm. Mean correction through the osteotomy site was 42.2 degrees (range, 31-55 degrees). Sagittal translation occurred in 40% of these patients. No vascular injury occurred. Although 3 patients developed lumbosacral pseudarthrosis, the COWO area was unaffected in all patients. Nine patients developed cephalad junctional kyphosis and 2 patients developed caudad junctional kyphosis. Most patients reported improvement in terms of pain, self-image, and function as well as overall satisfaction with the procedure. CONCLUSION: COWO is a useful procedure for patients with sagittal imbalance requiring more than 35 degrees lordotic correction through the osteotomy site. A worse clinical result is associated with increasing patient comorbidities, pseudarthrosis in lumbosacral fusion, and junctional kyphosis.

Enhanced capacity for spontaneous correction of lumbar curve in the treatment of major thoracic-compensatory C modifier lumbar curve pattern in idiopathic scoliosis.

STUDY DESIGN: Retrospective radiographic review. OBJECTIVE: To evaluate the outcome of maximal selective thoracic correction with controllable corrective forces provided by cantilevel bending technique (CBT) for idiopathic scoliosis (IS) in the presence of widely deviated compensatory lumbar curve. SUMMARY OF BACKGROUND DATA: Current intraoperative instrumentation and fusion techniques for selective fusion involve undercorrection of the thoracic curve while allowing for spontaneous lumbar curve correction and maintaining overall coronal balance. Since the lumbar curve is nonstructural and compensatory, procedures for selective thoracic fusion should approximate the best possible correction of thoracic curve such that resultant spontaneous lumbar curve correction and compensation is maximized. METHODS: Thirty-seven consecutive IS patients with main thoracic compensatory minor "C" modifier lumbar curves underwent maximal selective thoracic correction by CBT at a single institution. Radiographs were analyzed before surgery, immediately after surgery, and at most recent follow-up (range, 2-6 years). RESULTS: A mean 83% thoracic correction was closely matched by a 81% lumbar correction at most recent follow-up. The mean thoracic curve correction/flexibility ratio was 2.4. Enhanced capacity for spontaneous correction of lumbar curve was evidenced by the mean correction/flexibility ratio of 1.2. Spontaneous correction of lumbar apical translation occurred in all patients. Global coronal imbalance was common before surgery (mean, 11 mm), and remained similarly so after surgery (mean, 12 mm). CONCLUSION: Use of CBT facilitates 3-dimensional control of corrective forces and allows for maximum selective instrumentation-assisted thoracic and spontaneous lumbar curve correction in patients with Lenke 1C or 2C IS.