Correlation between Disc Imaging Observations and Clinical Efficacy after Percutaneous Endoscopic Lumbar Discectomy: A 1-Year Follow-up Study.

OBJECTIVE: The connection between alterations in the disc structure following percutaneous endoscopic lumbar discectomy (PELD) and symptoms in patients postsurgery has not been reported yet. The purpose of the present study was to discuss the potential correlation between the changes in the morphological characteristics of various reference surfaces of the intervertebral disc after percutaneous endoscopic lumbar discectomy (PELD) and clinical outcomes, to identify the morphological parameters that affect efficacy and provide an evidence-based foundation for assessing postoperative efficacy. METHODS: From October 2019 to October 2021, after percutaneous endoscopic lumbar discectomy (PELD), 98 individuals were enrolled. MRI DICOM data of the lumbar spine were obtained before and after surgery, specifically around 3 months. The morphological parameters of the operated and adjacent segments of the discs were measured using T2-weighted images from three reference planes. Outcomes were assessed using the Oswestry disability index (ODI), visual analogue pain scores for the back and leg (VAS-back/VAS-leg), Japanese Orthopaedic Association (JOA) scores, and recovery rates. Postoperative changes in disc parameters and outcomes were compared between patients with different severity and types of LDH based on the MSU staging. Patients completed the questionnaire during outpatient follow-up appointments 3, 6, and 12 months after the surgery. The follow-up period was 14.69 ± 4.21 months, ranging from 12 to 24 months. RESULTS: Parameters such as area and circumference of intervertebral discs in the cross-section were not associated with the change in the efficacy index. Postoperatively, a negative correlation between the variation of the disc height, disc height index, and protrusion distance and the difference in VAS scores for low back pain at 3 and 6 months was observed among the two sagittal change parameters. Differences between changes in disc imaging parameters and postoperative efficacy were not statistically significant between various types of lumbar disc herniation. CONCLUSION: For the patients after percutaneous endoscopic lumbar discectomy, the changes in parameters such as disc area and circumference in the cross-sectional plane are not associated with efficacy, and the changes in disc height and herniation distance in the sagittal plane provide a morphologic basis for the assessment of short-term postoperative efficacy. In addition, the changes in disc morphologic parameters and postoperative efficacy do not differ between various types of lumbar disc herniation.

[Clinical efficacies of skipping two-level transpedicular wedge osteotomy for correction of severe kyphosis in ankylosing spondylitis].

OBJECTIVE: To explore the clinical efficacies of skipping two-level transpedicular wedge osteotomy in the correction of severe kyphotic deformity in ankylosing spondylitis (AS). METHODS: From January 2003 to December 2009, a total of 38 consecutive patients with AS and severe kyphosis (chin-brow vertical angle (CBVA) or global thoraco-lumbar kyphosis angle (TLKA) over 70°) undergoing skipping two-level transpedicular wedge osteotomy at the Department of Orthopedics of Chinese PLA General Hospital were reviewed retrospectively. There were 32 males and 6 females with an average age of 38.0 years (range: 22 - 65). The preoperative parameters of TLKA, T11-L2 kyphotic angle, L1-S1 lordosis angle, sagittal imbalance and CBVA were obtained from the total spine radiography or computed tomography and clinical lateral photograph. According to the characteristic curves and normal spinal alignment, their profiles of osteotomy location and angle were determined and confirmed by computer simulations. Improvement in postoperative parameters was observed and treatment satisfaction evaluated RESULTS: The average operating duration was 309 minutes and the average volume of blood loss was 2050 ml. The parameters of TLKA, T11-L2 kyphotic angle and L1-S1 lordosis angle improved from 101.0° ± 21.3°, 45.2° ± 13.6°, -28.2° ± 23.3° at preoperation to 26.0° ± 12.1°, 2.8° ± 11.6°, 28.9° ± 13.3° postoperation respectively (P < 0.01). CBVA improved from 79.4° ± 15.9° to 13.6 ° ± 10.9° (P < 0.01). The sagittal imbalance distance improved from (49 ± 13) to (15 ± 7) cm (P < 0.01). All patients could walk with orthophoria and lie horizontally postoperatively. The average follow-up was 32 months (range: 24 ∼ 78 months). Fusion of osteotomy was achieved in all patients and there was no event of loss of correction or implant failure. The SRS-22 average score improved from 1.8 to 4.2. CONCLUSION: For severe kyphosis in AS, skipping two-level transpedicular wedge osteotomy is a satisfactory and reliable approach for the correction of kyphotic deformity and it may improve appearance and function significantly.

[One-stage total en bloc spondylectomy and reconstruction via a single posterior approach for thoracic vertebral symptomatic hemangioma associated with spinal cord dysfunction].

OBJECTIVES: To investigate the surgical results of one-stage total en bloc spondylectomy (TES) and reconstruction via a single posterior approach for thoracic symptomatic vertebral hemangioma associated with spinal cord dysfunction and evaluate its curative effect. METHODS: A total of 9 patients treated with one-stage TES (7 cases) and total vertebrectomy (2 cases) by posterior approach from March 2006 to January 2010 were retrospectively reviewed. The cases included 2 males and 7 females with a median age of 33.6 years (range 14 to 77 years), and with 1 case of Grade A, 3 cases of Grade B, 3 cases of Grade C, 2 cases of Grade D according to Frankel grade system. All patients suffered from moderate to severe pain and neurological deficit with an average symptom duration of 14.4 months (range 3 - 24 months) MRI revealed severe spinal cord compression. The spinal reconstruction was obtained by titanium mesh filled with autograft and posterior internal fixation with rod-screw system. RESULTS: The operation time was 210 minutes on average (180 - 270 minutes) and the average blood loss was 1800 ml (1000 - 5000 ml). The follow-up period lasted from 18 months to 5 years. All cases with preoperative pain relieved after operation. The visual analogue scale pain scores decreased to 1.1 from 8.3 at 3 months after surgery. No disruption of dural mater, cerebrospinal fluid leakage, iatrogenic spinal cord injury and major vessel damage occurred. Up to now, there was no local recurrence in all cases. Significant neurological function improvement was achieved in all patients with one to three grades in Frankel grade system. Fusion of the autograft was well achieved and no internal fixation failure in all patients. CONCLUSIONS: One-stage TES and spine reconstruction by a single posterior approach is feasible, safe and effective to this disease. It is favourable in decreasing the hemangioma recurrence and improvement of the neurological function.

[Animal experiment of memory alloy staples to control the sagittal growth of vertebrates].

OBJECTIVE: To present that Nickel-Titanium (NT) memory alloy staples in fusionless controlling the growth of the vertebrates in the sagittal plane. METHODS: Eighteen infant female goats were selected and equally divided into 3 random groups: long staple group, short staple group and blank control group. Five long staple (the legs' length = 7 mm) and five short staple (the legs' length = 4 mm) were implanted into each goat in long and short staple groups respectively by anterior approach, right on the front of the thoracic vertebrae from T(6) to T(11). The control group was not given any treatment. X-ray examination was performed pre-operatively and post-operatively. Cobb angle of lateral radiograph was measured and the data of Cobb angle were statistically analyzed. At the end of the experiment, whether the staples implanted spinal columns were fused or not were evaluated by gross observation. RESULTS: Finally, all of the goats were included in the final results. Before the operations, T(6-11) sagittal Cobb angle was 7.0° ± 2.3° in short staple group, and 6.2° ± 4.0° in long staple group. And after the operation, the T(6-11) Cobb angle was increased to 12.7° ± 4.7° in short staple group with the increased rate of 81.4%, and 14.0° ± 4.9° in long staple group with the increased rate of 125.8%, respectively. Before and after the surgery, there were no significant differences between long staple group and short staple group in terms of Cobb angle (pre-operation P = 0.655, post-operation P = 0.596). Before the surgery, there were no differences in terms of Cobb angle, between long staple groups and control group (P = 0.929), and short staple groups and control group (P = 0.720). At the end of the experiment, there were significant differences between long staple group and control group in terms of Cobb angle (P = 0.007), and between short staple group and control group (P = 0.021). The staples implanted spinal columns were not fused which was proved by gross observation. CONCLUSIONS: The memory alloy staple implantation by anterior approach, right on the front of the thoracic vertebrae of goats, can control the growth of thoracic vertebrates leading to kyphosis.

Correlation of Acetabular Anteversion and Thoracic Kyphosis Postoperatively with Proximal Junctional Failure in Adult Spinal Deformity Fused to Pelvis.

OBJECTIVES: To investigate whether the immediate thoracic kyphosis (TK) and acetabular anteversion (AA) postoperatively are correlated with proximal junctional failure (PJF) in adult spinal deformity (ASD) patients underwent surgical treatment. METHODS: This is a retrospective study. Following institutional ethics approval, a total of 57 patients (49 Female, eight Male) with ASD underwent surgery fused to sacroiliac bone (S1, S2, or ilium) from March 2014 to January 2019 were included. All of those patients were followed up for at least 2 years. Demographic, radiographic and surgical data were recorded. The maximum range of flexion motion (F-ROM) and extension motion (E-ROM) actively of hip joints was measured and recorded at pre- and postoperation. The sum of F-ROM and E-ROM was defined as the range of hip motion (H-ROM). Receiver operating characteristic (ROC) curve analysis was used to obtain the cut off value of parameters for PJF. A Kaplan-Meier curve and log-rank test were used to analyze the differences in PJF-free survival. RESULTS: In all, 14 patients developed PJF during follow-up. Comparisons between patients with and without PJF showed significant differences in immediate TK (P < 0.001) and AA (P = 0.027) postoperatively. ROC curve analysis determined an optimal threshold of 13° for immediate AA postoperatively (sensitivity = 74.3%, specificity = 85.7%, area under the ROC curve [AUC] = 0.806, 95% CI [0.686-0.926]). Nineteen patients with post-AA ≤13° were assigned into the observational group, and 38 patients with post-AA >13° were being as the control group. Patients in the observational group had smaller H-ROM (P = 0.016) and F-ROM (P < 0.001), but much larger E-ROM (P < 0.001). There were 10 patients showing PJF in the observational group and four in the control group (10/9 vs 4/34, P < 0.001). PJF-free survival time significantly decreased in the observational group (P = 0.001, log-rank test). Furthermore, patients in the observational group had much larger TK (post-TK, P = 0.015). The optimal threshold for post-TK (sensitivity = 85.7%, specificity = 76.7%; AUC = 0.823, 95% CI [0.672-0.974]) was 28.1° after the ROC curve was analyzed. In the observational group, those patients with post-TK ≥28.1° had significantly higher incidence of PJF (9/2 vs 1/7, P < 0.001) than those with post-TK < 28.1°. Moreover, PJF-free survival time in those patients significantly decreased (P = 0.001, log-rank test). CONCLUSIONS: ASD patients with acetabular anteversion of ≤13° at early postoperation may suffer significantly restricted hip motion and much higher incidence of PJF during follow-up, moreover, in those patients, postoperative TK ≥28.1° would be a significant risk factor for PJF developing.

Association of Sagittal Spinopelvic Realignment with Correction in Lower Lumbar Lordosis after Surgical Treatment in Degenerative Lumbar Scoliosis.

OBJECTIVE: To assess the effect that correction of lower lumbar lordosis (3L) has on global spine realignment due to the key role of 3L for scoliosis surgery in patients with degenerative lumbar scoliosis (DLS). METHODS: This study is a retrospective review performed between June 2018 and January 2020, including consecutive patients with DLS. Only patients age ≥ 45 years who had already undergone a selective root block operation and had the procedure of long-fusion extending to pelvis and posterior lumbar interbody fusion (PLIF) at lower lumbar spine (L4 -S1 ) were retained for analysis. Spinopelvic parameters measured included thoracic kyphosis (TK), lumbar lordosis (LL), 3L, pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), T1 pelvic angle (TPA), and sagittal vertical axis (SVA) at pre-operation and the third month follow-up. The mismatch (PI-LL) was calculated subsequently. Pearson correlation and linear regression analysis were performed to explore the association of the changes in global spinopelvic parameters with 3L correction. RESULTS: Thirty-nine patients (five males, 34 females) with the average age of 63.84 years (SD 7.53; range, 45-75 years) at the time of surgery were identified. All patients had the surgical procedure of long-fusion (≥4 vertebras) with PLIF at lower lumbar spine between L4 and S1 spine. Lower instrumented vertebras (LIV) fused to pelvis (S1 , 14; S2 , 18; ilium, 7) were operated in all patients. Seventeen patients were with upper instrumented vertebras (UIV) at thoracolumbar spine (L2 -T11 ), and 22 patients at thoracic spine (T10 and above). The median of instrumented segments was 10 (5-14). 3L significantly increased (P = 0.02) after surgical treatment by mean change of 4.21° (range, -19.7° to +22.2°). Perioperatively, all spinopelvic parameters regarding to TK, LL, SS, PT, TPA, SVA, and mismatch (PI-LL) had significant changes (P < 0.001). The change in 3L correlated significantly with the changes in spinopelvic parameters (r = 0.772 for LL, -0.589 for SVA, -0.439 for TPA, and -0.428 for PI-LL). After linear regression analysis, the formulas were obtained: d-LL = 14.977 + 0.636 × d-3L, (R2 = 0.596); d-(PI-LL) = 16.575 + 0.62 × d-3L, (R2 = 0.183); d-TPA = -7.284 to 0.358 × d-3L, (R2 = 0.193); d-SVA = -30.556-2.639 × d-3L (R2 = 0.347). CONCLUSIONS: Correction in lower lumbar lordosis, following the surgical procedure of long-fusion with PLIF at lower lumbar spine, could result in significant changes in full-spine parameters. The significant association of changes in each of global spine parameter with the correction of 3L perioperatively could provide important information for surgeons to make a surgical plan for spinal correction.

Pedicle Subtraction Osteotomy in Lateral Position: A New Strategy for Correcting Severe Thoracolumbar Kyphosis Combined with Hip Flexion Contracture in Ankylosing Spondylitis.

OBJECTIVE: To describe spinal osteotomy in lateral position, which might be a new strategy for correcting thoracolumbar kyphotic deformity combined with severe hip flexion contracture, and to present two cases in which this method was successfully performed. METHODS: Spinal osteotomies in lateral position were performed in two patients with severe thoracolumbar kyphosis combined with hip flexion contracture, which was not suitable for operation in the prone position. Case 1: a 33-year-old female AS patient still had severe hip flexion contracture due to poor rehabilitation after total hip replacement (THR). The range of movement of the hip was only about 15° in right and 10° in left. Pre-operativethoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), and sagittal vertical axis (SVA) were 52.4°, 49.1°, 42.7°, and 315 mm, respectively. Pedicle subtraction osteotomy (PSO) at L3 was performed in the lateral position. The eggshell procedure was used during osteotomy. Case 2: a 45-year-old male AS patient presented coexisting rigid thoracolumbar kyphosis and hip flexion contracture. The range of movement of the hip was only about 20° in right and 25° in left. Pre-operativeTK, TLK, LL and SVA were 34.9°, 66.8°, 58.8° and 290.8 mm, respectively. PSO at L2 was performed in lateral position. The eggshell procedure was also used. RESULTS: Sagittal malalignments of both patients were greatly improved. For case 1, the total operation time was 5.5 h. The blood loss was 1500 mL and the amount of allogeneic blood transfusion was 1580 mL during the operation. SVA was reduced to 127 mm and LL decreased from preoperative 42.7° to -28.4°. The correction angle through L3 was 34.7° and the correction angle through the osteotomy segment was 62.9°. For case 2, the duration of surgery was 6.5 h. The operative blood loss was 2000 mL and the total amount of blood transfusion was 2020 mL. SVA was reduced to 209.8 mm and LL decreased from preoperative 58.8° to 9.2°.The correction angle through L2 was 37.1° and the correction angle through the osteotomy segment was 55°. No intra-operative or post-operative complications were observed. Six months after PSO, case 1 had good posture for standing and sitting. The case 2 underwent bilateral THRs nine months after PSO. CONCLUSION: PSO could be performed in the lateral position successfully. For AS patients who cannot be placed in the prone position due to coexisting severe thoracolumbar kyphosis and hip flexion contracture, performing spinal osteotomy in the lateral position as the first step is an alternative.

[Vertebral column decancellation for the management of rigid scoliosis: the effectiveness and safety analysis].

OBJECTIVE: to explore the effectiveness and safety of vertebral column decancellation (VCD) for the management of rigid scoliosis. METHODS: from May 2004 to February 2008, 32 patients with rigid scoliosis underwent VCD were reviewed. There were 12 males and 20 females with an average age of 18 years (range, 10 - 56 years). The operation techniques included multilevel vertebral body decancellation and residual intervertebral disc resection, followed by realignment and posterior correction with pedicle screws. The effectiveness was evaluated by preoperative and postoperative radiography and three-dimensional CT scan reconstruction at final follow-up. The intraoperative and postoperative complications of all patients were recorded. RESULTS: a mean of 2.1 vertebrae were performed with VCD and a mean of 10.6 vertebral levels were instrumented and fused (range, 8 - 13 vertebrae). The mean duration of surgery was 270 minutes (range, 215 - 380 minutes). The average intraoperative blood loss was 1560 ml (range, 900 - 4800 ml). Complications were encountered in 4 patients. There were 2 cases with transient neurological deficits, 1 case with CSF leak, 1 case with epidural hematoma. The average time of follow-up was 31 months (range, 24 - 48 months). The correction rate was 61% on the coronal plane (from 108° to 42°), and the correction rate was 65% on the sagittal plane (from 82.0° to 28.7°). All patients had solid fusion at osteotomy site, and no instrumentational failure and loosening were found over the follow up. CONCLUSION: single stage posterior VCD is an effective option to manage rigid scoliosis.

Low pelvic incidence is associated with Andersson lesions in ankylosing spondylitis patients with kyphosis.

INTRODUCTION/OBJECTIVES: This study was to investigate the role of pelvic incidence (PI) in the development of Andersson lesions (ALs) in ankylosing spondylitis (AS) patients with kyphosis and to evaluate the difference in sagittal spinopelvic parameters between inflammatory ALs and mechanical ALs. METHOD: A total of 135 AS patients with kyphosis were reviewed. The patients were classified into AL group and non-AL group based on the presence or absence of ALs. Additionally, AS patients with ALs were also classified as either inflammatory or mechanical lesions depending on the radiological features of the lesions. The sagittal spinopelvic parameters of all these AS patients were measured and compared. Logistic regression analysis was performed to determine the powerful variables for predicting ALs in AS patients. RESULTS: ALs were detected in 34 patients (25.2%) of the total 135 AS patients. The mean PI of the AL group was 40.0°, which was significantly lower than that (48.3°) of the non-AL group (P < 0.001). No statistically significant difference was observed in PI (P = 0.350) between the inflammatory lesion group and the mechanical lesion group. Logistic regression analysis showed that only PI was a statistically significant risk factor for ALs (P < 0.001) and was negatively correlated with ALs (odds ratio = 0.76). CONCLUSIONS: These data suggest that low PI is closely associated with ALs in AS patients with kyphosis and that it might be a possible risk factor for the development of ALs. Moreover, both inflammatory and mechanical ALs patients had similarly low PI.Key Points• Low PI was closely associated with ALs in AS patients with kyphosis and might be a possible risk factor for development of ALs.• Either inflammatory or mechanical ALs patients had similar low PI.

Compensatory Mechanism of Maintaining the Sagittal Balance in Degenerative Lumbar Scoliosis Patients with Different Pelvic Incidence.

OBJECTIVE: To investigate the compensatory mechanism of maintaining the sagittal balance in degenerative lumbar scoliosis patients with different pelvic incidence (PI). METHODS: This was a retrospective imaging observation study. Patients in our department with degenerative lumbar scoliosis between 2017 and 2019 were reviewed. A total of 36 patients were eligible and included in the present study. The average age of those patients was 64.22 years, including 8 men and 28 women. The coronal and sagittal parameters were measured on full-length spine X-ray film, including globe kyphosis (GK), lumber lordosis (LL), thoracolumbar kyphosis (TLK), thoracic kyphosis (TK), sagittal vertical axis (SVA), sagittal shift angle, Cobb angle, coronal shift angle, and vertebra. The anterior pelvic plane angle (APPA) and pelvic parameters were also measured, including the pelvic tilt (PT), the PI, and the sacral slope (SS). PI-LL, LL-SS, and GK-SS were calculated. Traditional pelvic tilt was also calculated using the following formula: cPT = PI × 0.37-7. These patients were divided into two groups according to their PI values. The patients' PI value in Group 1 was smaller than 50°. The patients' PI value in Group 2 was equal to or larger than 50°. RESULTS: These patients' SS, PT, PI, LL, TLK, TK, and GK were 28.70° ± 11.36°, 23.28° ± 6.55°, 52.00° ± 11.03°, 31.66° ± 14.12°, 12.12° ± 14.9°, 17.81° ± 13.53°, and -13.17° ± 16.27°. The sagittal shift angle, the APPA, the Cobb angle, the coronal shift angle, vertebra, PI-LL, cPT, APPA-4, LL-SS, and GK-SS were 4.38° ± 5.75°, -12.55° ± 8.83°, 30.03° ± 12.59°, 2.40° ± 2.13°, 4.08 ± 0.93, 19.86° ± 10.97°, 12.35° ± 4.55°, -8.30° ± 9.07°, 3.30° ± 8.82°, and 15.53° ± 9.83°, respectively. There was no significant difference between PT and cPT + APPA-4 or between cPT and PT-APPA+4. There was significant difference between PT and cPT + APPA or between cPT and PT-APPA. This demonstrated that the APPA-4 is reliable as degree of the pelvic sagittal retroversion. There were significant differences in SS, PI, LL, TLK, GK, APPA, PT-APPA, PT-APPA+4, cPT, and APPA-4 between Group 1 and Group 2. There were no significant differences in PT, TK, sagittal shift angle, SVA, Cobb angle, coronal shift angle, vertebra number, PI-LL, cPT + APPA, cPT + APPA-4, LL-SS, and GK-SS between Group 1 and Group 2. The Pearson tests showed that PI-LL had significant correlations with TK, LL, sagittal shift angle, SVA, and LL-SS. There was no significant correlation between PI-LL and Cobb angle, GK, TLK, APPA, vertebra, Coronal Shift Angle, or GK-SS. CONCLUSION: The APPA-4 is reliable as degree of the pelvic sagittal retroversion. In degenerative lumbar scoliosis, patients with smaller PI tended to rely more on the pelvic retroversion to maintain the sagittal balance than patients with larger PI, or patients with smaller PI were likely to start up the pelvic retroversion compensatory mechanism earlier than the patients with larger PI.

[An experimental study of correction of idiopathic-type scoliosis by staple].

OBJECTIVE: To evaluate the feasibility of the correction idiopathic-type scoliosis by implanting the staple in growing animal models. METHODS: Fourteen female goats were performed unilateral pedicle screws asymmetric tethering in left side in combination with right rib resection (age: 5 to 8 weeks, weight: 6 to 8 kg). The observing time was about 8 weeks. Goats that had been created scoliosis model successfully were classified in 2 groups randomly. CONTROL GROUP: just removing the posterior tether, no treatment was offered. Correct group: the removing of posterior tether and the stapling of anterior spinal epiphysis were performed simultaneously. Dorsoventral and lateral plain radiographs were taken preoperatively and postoperatively. Serial X-ray postoperatively were performed every 4 weeks to measure the Cobb angle of the spine and to observe the condition of the insert. The observing time is about 8 weeks. RESULTS: Radiography showed that 12 goats had created scoliosis model successfully. CONTROL GROUP (n = 6): Series X-ray show that the change of the Cobb angle was not obviously. The initial curves after the procedures measured an average of 40.8 degrees (28 degrees-56 degrees), the average Cobb angle was 42.5 degrees (30 degrees-58 degrees) after 8 weeks, no statistics difference are found (P > 0.05). Treatment group (n = 6): no complication such as pedicel screw break, instrument loosen, dislocation, injury of blood vessel, nerve injury and organ injury of thoracic cavity etc, were found during the observing period. The initial curves after the procedures measured an average of 44.5 degrees (36 degrees-57 degrees), to some degree, the Cobb angle decreased and the average was 42.5 degrees (30 degrees-58 degrees) after 8 weeks. There are statistics difference between the initial and final curves (P < 0.05). CONCLUSION: As a means of mechanical modulation, stapling can be manipulate conveniently and safely, and can modulate the spinal growth of the animal model successfully, predicted that it may be a new selection for idiopathic-type scoliosis in growing children.

[Clinical outcomes of single level Bryan cervical disc arthroplasty: a prospective controlled study].

OBJECTIVE: To compare the clinical outcomes of single level Bryan cervical disc replacement with traditional anterior cervical discectomy and fusion (ACDF). METHODS: From Dec 2003 to May 2005, 59 patients with primary, single-level cervical radiculopathy and/or myelopathy were prospectively randomized into 2 groups: Bryan group with artificial disc replacement and ACDF group with traditional anterior cervical discectomy and fusion. Operation time, blood loss and hospitalization duration were compared between the 2 groups. Follow-up was taken at six weeks, 3, 6, 12 and 24 months after operation, and each case in both groups was evaluated with serial radiographic studies, neck disability indices (NDI), visual analog scale scores (VAS) for arm and neck pain. RESULTS: No difference was found in the operation time, intraoperative blood loss and hospital stay between the 2 groups. But at the follow-up of 6 weeks and 3 months after operation, significant difference in NDI and VAS of neck pain existed. All replaced segments remained normal range of motion in sagittal rotation, while no motion occurred in any of the fusion segments. In ACDF group movement of the whole cervical spine decreased but gradually recovered to preoperative level in 6 months after operation. In Bryan group, pre- and postoperative motion of the whole cervical spine remained unchanged at any of the follow-up time. CONCLUSIONS: Bryan disc replacement can achieve similar clinical improvement compared with traditional ACDF. Arthroplasty has the advantages of motion maintenance for the cervical spine and short recovery time after operation.

Proposal of a New Treatment-Oriented Classification System for Spinal Deformity in Ankylosing Spondylitis.

OBJECTIVE: To describe and apply an optimal classification system for the management of ankylosing spondylitis (AS) that may be appropriate to make a preoperative surgical plan. BACKGROUND: The treatment choices of ankylosing spondylitis kyphosis remain controversial. The lack of a widely accepted classification system contributes to the variation in surgical decision making. METHODS: The classification is mainly based on radiographic findings. The sagittal deformity of spine in ankylosing spondylitis is classified according to three criteria: the location of the apex, the lumbar modifier (A, lumbar lordosis <0°, and B, lumbar kyphosis >0°) and the thoracic/thoracolumbar kyphosis severity modifier (- or +). RESULTS: The ankylosing spondylitis kyphosis can be divided into 4 types according to the location of the apex: Type I (lumbar), Type II (thoracolumbar), Type III (thoracic), Type IV (cervical or cervicothoracic junction). Either Type II or Type III is further divided into four subtypes based on the lumbar modifier and the thoracic/thoracolumbar kyphosis severity modifier: Type IIA-, Type IIA+, Type IIB-, Type IIB+, Type IIIA-, Type IIIA+, Type IIIB-, and Type IIIB+. Surgical decision making for AS kyphosis can be made according to the new classification. CONCLUSION: This new classification system can be used effectively to classify AS kyphosis, which can be used to guide surgical decision making, including determining the site and the levels of osteotomies. Further research may be needed to validate the classification.

[Experimental study on controlling unilateral spine growth by shape memory alloy staple].

OBJECTIVE: To observe the effects that shape memory alloy (SMA) staples implanted to the lateral aspect of the thoracic vertebrae on spinal growth in goats. METHODS: Sixteen goats (age 2 - 3 months) were divided into 3 groups: six in single staple group; six in double staples group and four in control group. Single staples group underwent right-side thoracotomy for exposing the thoracic spine through the eighth rib. Five SMA staples were placed laterally into vertebral bodies of T(6 - 11) spanning discs. Double staples group underwent the same operation. Laterally directed 10 SMA staples were placed into vertebrae of T(6 - 11) spanning discs and two staple spanning each disc. The last four goats in control groups just only underwent right-side thoracotomy. In the next 4 months after operation, radiographs were taken to observe the spinal growth every month. RESULTS: The radiographic analysis demonstrated scoliosis of 12.83 degrees +/- 12.17 degrees in single staple group and 12.00 degrees +/- 3.22 degrees in double staple group after 2 months of the operation. Cobb angle of 6.00 degrees +/- 4.94 degrees and 25.17 degrees +/- 3.71 degrees were observed in the two groups respectively after 4 months of operation, as compared with 0 degrees in the control groups. Only 2 goats developed kyphosis. CONCLUSIONS: Compression between vertebral bodies by SMA staples can depress spinal growth in the same side and greater compression result in larger curves.

Three-dimensional computed tomography for assessing lung morphology in adolescent idiopathic scoliosis following posterior spinal fusion surgery.

OBJECTIVE: To evaluate the changes in lung morphology in subjects with adolescent idiopathic scoliosis (AIS) following posterior spinal fusion surgery. METHODS: From April 2009 to August 2013, 30 AIS patients (nine males and 21 females) were enrolled in this study. All scans were obtained with the patient in the supine position and the breath held in deep inspiration and performed both before and after surgery. Syngo software was used to manage the computed tomography scan imaging and to calculate the lung volume, lung height and pulmonary cross-sectional area in the apical vertebral plane. RESULTS: Left lung, right lung and total lung volumes and convex to concave lung volume ratio did not change significantly after corrective surgery. There was a statistically significant improvement in left lung and right lung heights after posterior spinal fusion surgery. However, the pulmonary cross-sectional area in the apical vertebrae plane was smaller postoperatively than preoperatively. CONCLUSIONS: This study showed that lung height in AIS patients increased significantly immediately postoperatively whereas lung volume did not change significantly. Thoracic symmetry was improved postoperatively in these patients.

Two-level spinal osteotomy for severe thoracolumbar kyphosis in ankylosing spondylitis. Experience with 48 patients.

STUDY DESIGN: A retrospective study. OBJECTIVE: To report surgical results for severe thoracolumbar kyphosis secondary to ankylosing spondylitis (AS) corrected with 2-level spinal osteotomy. SUMMARY OF BACKGROUND DATA: Transpedicular osteotomy in the lumbar spine is the major approach to correct kyphosis in AS. Most surgical procedures were performed at 1 level and only few literature report 2-level osteotomy in 1 patient. METHODS: From January 2003 to June 2011, we reviewed 48 patients experiencing AS with severe thoracolumbar kyphosis who underwent stage 2-level spinal osteotomy in our hospital. The osteotomies were performed at T12 and L2 or L1 and L3, according to the apex of kyphosis. Preoperative and postoperative height, chin-brow vertical angle, sagittal balance, and the sagittal Cobb angle of the vertebral osteotomy segment were documented. Intraoperative, postoperative, and general complications were recorded. RESULTS: The chin-brow vertical angle improved from 65.0° ± 28.0° to 5.0°± 10.0° (P = 0.000) and the sagittal imbalance distance improved from 26.9 ± 10.4 cm to 10.6 ± 5.6 cm (P = 0.000). The mean amount of correction was 24.9° at the superior site of the osteotomy and 38.1° at the inferior site of the osteotomy. Postoperatively, all patients could walk with horizontal vision and lie on their backs. No major acute complications such as death or complete paralysis occurred. Five patients experienced complications such as infections (n = 1) and cerebrospinal fluid leaks (n = 4). Both Oswestry Disability Index and Scoliosis Research Society scores improved largely. Fusion at the osteotomy site was achieved in each patient, and no implant failures were noted. CONCLUSION: Single-stage 2-level osteotomy can effectively and safely correct kyphotic deformities of the thoracolumbar spine caused by AS. LEVEL OF EVIDENCE: 3.

Positioning thoracic pedicle screw entry point using a new landmark: a study based on 3-dimensional computed tomographic scan.

STUDY DESIGN: A novel method to identify the entry point. OBJECTIVE: To quantify the position of thoracic pedicle screw entry points on the lamina at various segments of the thoracic vertebrae in normal subjects and patients with adolescent idiopathic scoliosis and propose a new technique to select entry points using a new landmark. SUMMARY OF BACKGROUND DATA: Thoracic pedicle screws have been widely used in thoracic surgery, and the placement of pedicle screws has been studied extensively. However, there are only qualitative studies on selecting the entry point, and no study has quantified the position of entry points. METHODS: A retrospective study using 3-dimensional computed tomographic reconstruction techniques were used to study the morphology of thoracic vertebrae in 110 adolescents (56 cases of adolescent idiopathic scoliosis and 54 normal subjects). A quantitative area was used to select the entry point. Thoracic pedicle screw entry point was determined using the new landmark as reference and thoracic pedicle screws were placed in 21 patients. Postoperative computed tomographic scanning was performed to assess the safety and effectiveness of this entry point selection technique. RESULTS: We determined that the accuracy of pedicle screw placing after positioning entry point using the quantitative area was significantly superior to that after positioning entry point using the traditional method (P < 0.05). CONCLUSION: The new technique quantifies the position of each thoracic pedicle screw entry point and it is convenient, easy to operate, and has relatively high accuracy of screw placement. This positioning technique can provide safe and accurate clinical guidance for selecting thoracic pedicle screw entry point.

Early posterior spinal canal decompression and circumferential reconstruction of rotationally unstable thoracolumbar burst fractures with neurological deficit.

BACKGROUND: Among the various treatments of neurologically involved unstable thoracolumbar burst fractures, the combination of anterior and posterior instrumentation provides the most stable reconstruction. However, the use of both approaches on a trauma patient may increase the morbidity. This study is a retrospective matched cohort study to evaluate the advantages of a single stage posterior approach for spinal canal decompression in combination with circumferential reconstruction by comparing the clinical and radiographic results. METHODS: From March 2005 to September 2009, patients with matched type spinal fracture, ages at surgery, and involved levels in our institute underwent either a single stage posterior approach (group one, n = 12) or traditional combined approach (group two, n = 14) for spinal canal decompression and circumferential reconstruction were reviewed. Pre- and post-operative X-ray flms were reviewed and changes in Cobb angle of thoracolumbar spine were documented. Intra-operative, post-operative, and general complications were registered. RESULTS: The mean follow-up was (27.7 ± 9.6) months (range, 14 to 56 months) in group one and (29.2 ± 7.4) months (range, 20 to 60 months) in group two (P > 0.05). The mean operation time was 214 minutes (range, 186 ± 327 minutes) in group one and 284 minutes (range, 219 ± 423 minutes) in group two (P < 0.05). The average volume of intraoperative blood loss was 1856 ml (range, 1250 ± 3480 ml) in group one and 2453 ml (range, 1600 ± 3680 ml) in group two (P < 0.05). There was no statistical difference between the groups one and two in average vertebral body height loss at the injured level and the average Cobb angle in sagittal plane before and immediately after surgery. Postoperatively, there was an epidural hematoma in one patient in group one and two patients in group two. Bony union after stabilization was obtained in all patients, without loosening or breakage of screws. Loss of correction (5°) was seen in 1 patient in group one at the 6th month owing to the subsidence of the Titanium mesh cages into the vertebra. In group two, totally four patients suffered respiratory-related complication, including pneumonia in two, severe atelectasis in one and pleural effusions in one. Importantly, there were no intraoperative or postoperative deaths in any group. All patients with incomplete neurologic deficits improved at least 1 Frankel grade. CONCLUSION: Single-stage posterior vertebra resection in combination with circumferential reconstruction is a new option to manage severe thoracolumbar burst fractures.

Scoliosis model created by pedicle screw tethering in immature goats: the feasibility, reliability, and complications.

STUDY DESIGN: An in vivo model of scoliosis was established in immature goats. OBJECTIVE: To assess the feasibility, reliability, and complications of the innovative animal model. SUMMARY OF BACKGROUND DATA: Among the methods of creating a scoliotic model, posterior asymmetric tethering of spine yielded encouraging results. However, some shortcomings associated with the use of posterior asymmetric tether are apparent. METHODS: Fourteen female goats (age: 5-8 weeks old, weight: 6-8 kg), were instrumented and tethered using unilateral pedicle screws and contralateral rib resections. Twelve of the goats were followed up for 8 weeks by serial radiography. Six goats were removed of the posterior load and no treatment was given. Two goats were selected randomly from the 6 animals and subjected to computed tomography (CT) three-dimensional reconstruction after another 8 weeks. All the 6 goats were killed and spine specimens were harvested for histologic study 16 weeks after observation. RESULT: Radiographic observation showed that 12 goats developed scoliosis with convex toward the right side, and the curvature increased with time in 11 goats, and it remained unchanged in 1 animal. The angle immediately after the procedures averaged 29.0 degrees (23 degrees -38 degrees ) and increased to an average of 43.0 degrees (36.0 degrees -58.0 degrees ) over a period of 8 to 10 weeks, with average angle increment being 14.0 degrees (P < 0.001). The curvature ceased to increase in 6 goats during the subsequent 2 months after the tether were removed (P > 0.05). Three-dimensional CT reconstruction revealed that the vertebral bodies were wedged, the 2 sides of the thoracic skeleton were asymmetric, and the vertebrae in the major curve were rotated. Histologic study revealed that the goats remained in growth stage and the growth potential of 2 sides of the spine was not identical. CONCLUSION: Radiography and three-dimensional CT reconstruction of vertebrae revealed that the architectural alterations found in the model were similar to those of idiopathic-type deformity observed in clinical practice.