METHODS: Patient records were obtained from the Adult Symptomatic Lumbar Scoliosis-1 (ASLS-1) database, an NIH-sponsored multicenter, prospective study. Inclusion criteria were as follows: patients aged 40-80 years undergoing primary surgeries for ASLS (Cobb angle ≥ 30° and Oswestry Disability Index ≥ 20 or Scoliosis Research Society-22r ≤ 4.0 in pain, function, and/or self-image) with instrumented fusion of ≥ 7 levels that included the sacrum/pelvis. Patients with and without RF were compared to assess risk factors for RF and revision surgery.
RESULTS: Inclusion criteria were met by 160 patients (median age 62 years, IQR 55.7-67.9 years). At a median follow-up of 5.1 years (IQR 3.8-6.6 years), there were 92 RFs in 62 patients (38.8%). The median time to RF was 3.0 years (IQR 1.9-4.54 years), and 73% occurred > 2 years following surgery. Based on Kaplan-Meier analyses, estimated RF rates at 2, 4, 5, and 8 years after surgery were 11%, 24%, 35%, and 49%, respectively. Baseline radiographic, clinical, and demographic characteristics were similar between patients with and without RF. In Cox regression models, greater postoperative pelvic tilt (HR 1.895, 95% CI 1.196-3.002, p = 0.0065) and greater estimated blood loss (HR 1.02, 95% CI 1.005-1.036, p = 0.0088) were associated with increased risk of RF. Thirty-eight patients (61% of all RFs) underwent revision surgery. Bilateral RF was predictive of revision surgery (HR 3.52, 95% CI 1.8-6.9, p = 0.0002), while patients with unilateral nondisplaced RFs were less likely to require revision (HR 0.39, 95% CI 0.18-0.84, p = 0.016).
CONCLUSIONS: This study provides what is to the authors' knowledge the highest-quality data to date on RF rates following ASLS surgery. At a median follow-up of 5.1 years, 38.8% of patients had at least one RF. Estimated RF rates at 2, 4, 5, and 8 years after surgery were 11%, 24%, 35%, and 49%, respectively. Greater estimated blood loss and postoperative pelvic tilt were significant risk factors for RF. These findings emphasize the importance of long-term follow-up to realize the true prevalence and cumulative incidence of RF.
SUMMARY OF BACKGROUND DATA: Prolonged operation duration in adolescent idiopathic scoliosis (AIS) surgery was associated with increased perioperative complications. However, the factors affecting operation duration in AIS surgery were unknown.
OBJECTIVE: The aim of the study was to investigate the factors affecting operation duration in posterior spinal fusion (PSF) surgery using a dual attending surgeon strategy among Lenke 1 and 2 AIS patients.
METHODS: In all, 260 AIS patients with Lenke 1 and 2 curves who underwent PSF were retrospectively reviewed. Preoperative and intraoperative factors affecting operation duration such as age, sex, height, weight, body mass index, Risser grade, Lenke subtypes, number of fusion level, number of screws, screw density, wound length, upper and lowest instrumented vertebrae level, preoperative Cobb angle, and flexibility of the major curve were assessed using univariate and multivariate linear regression analyses. Independent factors were determined when P-value <0.05.
RESULTS: The mean operation duration was 122.2±28.6 minutes. Significant independent factors affecting operation duration in PSF among Lenke 1 and 2 AIS patients were Lenke 2 subtypes (β=8.86, P=0.008), number of screws (β=7.01, P<0.001), wound length (β=1.14, P=0.009), and flexibility of the major curve (β=-0.25, P=0.005). The overall model fit was R2=0.525. Operation duration can be predicted using the formula: (8.86×Lenke subtypes)+(7.01×number of screws)+(1.14×wound length)-(0.25×flexibility)-0.54, where Lenke 2=1 and Lenke 1=0.
CONCLUSION: The factors affecting operation duration in PSF among Lenke 1 and 2 AIS patients were Lenke 2 curves, number of screws, wound length, and curve flexibility. The knowledge of these factors enables the spinal deformity surgeons to plan and estimate the operation duration before AIS surgery.
METHODS: This was a retrospective study aimed to evaluate the perioperative outcome of single-staged PSF in severe rigid idiopathic scoliosis patients (Cobb angle ≥90° and ≤30% flexibility). Forty-one patients with severe rigid idiopathic scoliosis who underwent single-staged PSF were included. The perioperative outcome parameters were operation duration, intraoperative blood loss, intraoperative hemodynamic parameters, preoperative and postoperative hemoglobin, transfusion rate, patient-controlled anesthesia morphine usage, length of postoperative hospital stay, and perioperative complications. Radiological parameters included preoperative and postoperative Cobb angle, correction rate, side-bending flexibility, and side-bending correction index.
RESULTS: The mean age was 16.9 ± 5.6 years. The mean preoperative Cobb angle was 110.8 ± 12.1° with mean flexibility of 23.1 ± 6.3%. The mean operation duration was 215.5 ± 45.2 min with mean blood loss of 1752.6 ± 830.5 mL. The allogeneic blood transfusion rate was 24.4%. The mean postoperative hospital stay was 76.9 ± 26.7 h. The mean postoperative Cobb angle and correction rate were 54.4 ± 12.8° and 50.9 ± 10.1%, respectively. The readmission rate in this cohort was 2.4%. Four perioperative complications were documented (9.8%), one somatosensory evoke potential signal loss, one superficial infection, one lung collapse, and one superior mesenteric artery syndrome.
CONCLUSIONS: Severe rigid idiopathic scoliosis treated with single-staged PSF utilizing a dual attending surgeon strategy demonstrated an average correction rate of 50.9%, operation duration of 215.5 min, and postoperative hospital stay of 76.9 h with a 9.8% perioperative complication rate.
OBJECTIVE: To investigate the relationship between a +ve postoperative Upper Instrumented Vertebra (UIV) (≥0°) tilt angle and the risk of medial shoulder/neck and lateral shoulder imbalance among Lenke 1 and 2 Adolescent Idiopathic Scoliosis (AIS) patients following Posterior Spinal Fusion.
SUMMARY OF BACKGROUND DATA: Current UIV selection strategy has poor correlation with postoperative shoulder balance. The relationship between a +ve postoperative UIV tilt angle and the risk of postoperative shoulder and neck imbalance was unknown.
METHODS: One hundred thirty-six Lenke 1 and 2 AIS patients with minimum 2 years follow-up were recruited. For medial shoulder and neck balance, patients were categorized into positive (+ve) imbalance (≥+4°), balanced, or negative (-ve) imbalance (≤-4°) groups based on T1 tilt angle/Cervical Axis measurement. For lateral shoulder balance, patients were classified into +ve imbalance (≥+3°) balanced, and -ve imbalance (≤-3°) groups based on Clavicle Angle (Cla-A) measurement. Linear regression analysis identified the predictive factors for shoulder/neck imbalance. Logistic regression analysis calculated the odds ratio of shoulder/neck imbalance for patients with +ve postoperative UIV tilt angle.
RESULTS: Postoperative UIV tilt angle and preoperative T1 tilt angle were predictive of +ve medial shoulder imbalance. Postoperative UIV tilt angle and postoperative PT correction were predictive of +ve neck imbalance. Approximately 51.6% of patients with +ve medial shoulder imbalance had +ve postoperative UIV tilt angle. Patients with +ve postoperative UIV tilt angle had 14.9 times increased odds of developing +ve medial shoulder imbalance and 3.3 times increased odds of developing +ve neck imbalance. Postoperative UIV tilt angle did not predict lateral shoulder imbalance.
CONCLUSION: Patients with +ve postoperative UIV tilt angle had 14.9 times increased odds of developing +ve medial shoulder imbalance (T1 tilt angle ≥+4°) and 3.3 times increased odds of developing +ve neck imbalance (cervical axis ≥+4°).
LEVEL OF EVIDENCE: 4.
OBJECTIVE: The primary objective of this study was to assess the conformity of the radiological neck and shoulder balance parameters throughout a follow-up period of more than 2 years.
SUMMARY OF BACKGROUND DATA: Postoperative shoulder and neck imbalance are undesirable features among Adolescent Idiopathic Scoliosis patients who underwent Posterior Spinal Fusion. There are many clinical and radiological parameters used to assess this clinical outcome. However, we do not know whether these radiological parameters conform throughout the entire follow-up period.
METHODS: This was a retrospective study done in a single academic institution. Inclusion criteria were patients with scoliosis who underwent posterior instrumented spinal fusion with pedicle screw fixation and attended all scheduled follow-ups for at least 24 months postoperatively. Radiological shoulder parameters were measured from both preoperative antero-posterior and postoperative antero-posterior radiographs. Lateral shoulder parameters were: Radiographic Shoulder Height, Clavicle Angle (Cla-A), Clavicle-Rib Intersection Difference, and Coracoid Height Difference. Medial shoulder and neck parameters were: T1 Tilt and Cervical Axis (CA).
RESULTS: The radiographs of 50 patients who had surgery done from November 2013 to November 2015 were analyzed. Mean age of this cohort was 16.3 ± 7.0 years. There were 38 (76%) female patients and 12 (24%) male patients. Mean final follow-up was 38.6 ± 5.8 months. When conformity assessment of the radiological parameter using the interclass coefficient correlation was done, we found that all parameters had significant correlation (P
METHODS: All surgeries were performed by minimally invasive technique with either percutaneous monoaxial or percutaneous polyaxial screws inserted at adjacent fracture levels perpendicular to both superior end plates. Fracture reduction is achieved with adequate rod contouring and distraction maneuver. Radiological parameters were measured during preoperation, postoperation, and follow-up.
RESULTS: A total of 21 patients were included. Eleven patients were performed with monoaxial pedicle screws and 10 patients performed with polyaxial pedicle screws. Based on AO thoracolumbar classification system, 10 patients in the monoaxial group had A3 fracture type and 1 had A4. In the polyaxial group, six patients had A3 and four patients had A4. Total correction of anterior vertebral height (AVH) ratio was 0.30 ± 0.10 and 0.08 ± 0.07 in monoaxial and polyaxial groups, respectively (p < 0.001). Total correction of posterior vertebral height (PVH) ratio was 0.11 ± 0.05 and 0.02 ± 0.02 in monoaxial and polyaxial groups, respectively (p < 0.001). Monoaxial group achieved more correction of 13° (62.6%) in local kyphotic angle compared to 8.2° (48.0%) in polyaxial group. Similarly, in regional kyphotic angle, 16.5° (103.1%) in the monoaxial group and 8.1° (76.4%) in the polyaxial group were achieved.
CONCLUSIONS: Monoaxial percutaneous pedicle screws inserted at adjacent fracture levels provided significantly better fracture reduction compared to polyaxial screws in thoracolumbar fractures.
METHODS: In total, 311 patients underwent erect whole spine anteroposterior, lateral and lower limb axis films. Radiographic measurements included Transilium Pelvic Height Difference (TPHD; mm), Hip Abduction-Adduction angle (H/Abd-Add; °), Lower limb Length Discrepancy (LLD; mm), and Pelvic Hypoplasia (PH angle; °). The incidence and severity of pelvic obliquity were stratified to Lenke curve subtypes in 311 patients. The causes of pelvic obliquity were analyzed in 57 patients with TPHD ≥10 mm.
RESULTS: The mean Cobb angle was 64.0 ± 17.2°. Sixty-nine patients had a TPHD of 0 mm (22.2%). The TPHD was <5 mm in 134 (43.0%) patients, 5-9 mm in 104 (33.4%) patients, 10-14 mm in 52 (16.7%) patients, 15-19 mm in 19 (6.1%) patients, and ≥20 mm in only 2 (0.6%) patients. There was a significant difference between the Lenke curve types in terms of TPHD (p = 0.002). L6 curve types had the highest TPHD of 9.0 ± 6.3 mm followed by L5 curves, which had a TPHD of 7.1 ± 4.8 mm. In all, 44.2% of L1 curves and 50.0% of L2 curves had positive TPHD compared to 66.7% of L5 curves and 74.1% of L6 curves which had negative TPHD. 33.3% and 24.6% of pelvic obliquity were attributed to PH and LLD, respectively, whereas 10.5% of cases were attributed to H/Abd-Add positioning.
CONCLUSIONS: 76.4% of AIS cases had pelvic obliquity <10 mm; 44.2% of L1 curves and 50.0% of L2 curves had a lower right hemipelvis compared to 66.7% of L5 curves and 74.1% of L6 curves, which had a higher right hemipelvis. Among patients with pelvic obliquity ≥10 mm, 33.3% were attributed to PH, whereas 24.6% were attributed to LLD.
OBJECTIVE: To determine whether the severity of the curve magnitude in Lenke 1 and 2 Adolescent Idiopathic Scoliosis (AIS) patients affects the distance and position of the aorta from the vertebra.
SUMMARY OF BACKGROUND DATA: There were studies that looked into the position of the aorta in scoliotic patients but none of them documented the change in distance of the aorta to the vertebra in relation to the magnitude of the scoliosis.
METHODS: Patients with Lenke 1 and 2 AIS who underwent posterior spinal fusion using pedicle screw construct and had a preoperative computed tomography (CT) scan performed were recruited. The radiological parameters measured on preoperative CT scan were: Aortic-Vertebral Distance (AVD), Entry-Aortic Distance (EAD), Aortic-Vertebral angle (AVA), Pedicle Aorta angle/Aortic Alpha angle (α angle), and Aortic Beta angle (β angle).
RESULTS: Thirty-nine patients were recruited. Significant moderate to strong positive correlation was found between AVD and Cobb angle from T8 to T12 vertebrae (r = 0.360 to 0.666). The EAD was generally small in the thoracic region (T4-T10) with mean EAD of less than 30 mm. Among all apical vertebrae, the mean AVD was 5.9 ± 2.2 mm with significant moderate-strong positive correlation to Cobb angle (r = 0.580). The mean α angle was 37.7 ± 8.7° with significant weak positive correlation with Cobb angle (r = 0.325).
CONCLUSION: The larger the scoliotic curve, the aorta was located further away from the apical vertebral wall. The aorta has less risk of injury from the left lateral pedicle screw breach in larger scoliotic curve at the apical region. The distance from the pedicle screw entry point to the wall of the aorta was generally small (less than 30 mm) in the thoracic region (T4-T10).
LEVEL OF EVIDENCE: 4.
OBJECTIVE: This study aimed to assess the radiological and clinical outcome of patients with Lenke 1C and 2C curves treated with STF.
STUDY DESIGN: This is a retrospective study.
PATIENT SAMPLE: A total of 44 patients comprised the study sample.
METHODS: Forty-four patients with Lenke 1C and 2C curves with adolescent idiopathic scoliosis who underwent STF were reviewed. Radiological parameters and Scoliosis Research Society (SRS)-22r scores were assessed preoperatively, postoperatively, and on final follow-up. The incidence of coronal decompensation, lumbar decompensation, and adding-on phenomenon were reported.
RESULTS: Mean follow-up duration was 45.1±12.3 months and mean age was 17.0±5.1 years. The preoperative middle thoracic and thoracolumbar/lumbar (MT:TL/L) Cobb angle ratio was 1.4±0.3 and the MT:TL/L apical vertebra translation (AVT) ratio was 1.6±0.8. Final follow-up coronal balance was -13.0±11.5 mm, main thoracic AVT was 6.9±11.8 mm, and lumbar AVT was -20.4±13.8 mm (p
METHODS: Patients included had the diagnosis of significant back pain caused by osteoporotic vertebral compression fracture secondary to trivial injury. All the patients underwent routine preoperative sitting lateral spine radiograph, supine stress lateral spine radiograph, and supine anteroposterior spine radiograph. The radiological parameters recorded were anterior vertebral height (AVH), middle vertebral height (MVH), posterior vertebral height (PVH), MVH level below, wedge endplate angle (WEPA), and regional kyphotic angle (RKA). The supine stress versus sitting difference (SSD) for all the above parameters were calculated.
RESULTS: A total of 28 patients (4 males; 24 females) with the mean age of 75.6 ± 7.7 years were recruited into this study. The mean cement volume injected was 5.5 ± 1.8 ml. There was no difference between supine stress and postoperative radiographs for AVH ( p = 0.507), PVH ( p = 0.913) and WEPA ( p = 0.379). The MVH ( p = 0.026) and RKA ( p = 0.005) were significantly less in the supine stress radiographs compared to postoperative radiographs. There was significant correlation ( p < 0.05) between supine stress and postoperative AVH, MVH, PVH, WEPA, and RKA. The SSD for AVH, PVH, WEPA, and RKA did not have significant correlation with the cement volume ( p > 0.05). Only the SSD-MVH had significant correlation with cement volume, but the correlation was weak ( r = 0.39, p = 0.04).
CONCLUSIONS: Dynamic mobility stress radiographs can predict the postoperative vertebral height restoration and kyphosis correction after vertebroplasty for thoracolumbar osteoporotic fracture with intravertebral clefts. However, it did not reliably predict the amount of cement volume injected as it was affected by other factors.
OBJECTIVE: To investigate the association between postoperative upper instrumented vertebrae (UIV) tilt angle with postoperative medial shoulder and neck imbalance.
SUMMARY OF BACKGROUND DATA: Studies had found that current recommendations for UIV selection were not predictive of good postoperative shoulder balance.
METHODS: A total of 98 patients with adolescent idiopathic scoliosis with Lenke 1/2 curves who underwent posterior spinal fusion between 2013 and 2014 with minimum follow-up of 2 years were recruited. Radiological parameters: UIV tilt angle, T1 tilt, cervical axis, and clavicle angle were measured preoperatively, postoperatively, and at final follow-up.
RESULTS: Mean age was 16.2 ± 6.2 years. Mean follow-up was 37.9 ± 6.5 months. There were 73.5% Lenke 1 and 26.5% Lenke 2 curves. Significant factors affecting postoperative T1 Tilt were postoperative UIV tilt angle, preoperative T1 tilt, and preoperative UIV tilt angle. Postoperative UIV tilt angle and preoperative cervical axis were significant factors affecting cervical axis at final follow-up. UIV level was not significant independent factor that affected postoperative T1 tilt and cervical axis. There was strong correlation between postoperative UIV tilt angle and T1 tilt for the whole cohort (P
METHODS: The scoliosis curves were divided into eight zones. CT scans were used to assess perforations: Grade 0, Grade 1( 4 mm). Anterior perforations were classified into Grade 0, Grade 1( 6 mm). Grade 2 and 3 (except lateral grade 2 and 3 perforation over thoracic vertebrae) were considered as 'critical perforations'.
RESULTS: 1986 screws in 137 patients were analyzed. The overall perforation rate was 8.4% after exclusion of the lateral perforation. The highest medial perforation rate was at the transitional proximal thoracic (PT)/main thoracic (MT) zone (6.9%), followed by concave lumbar (6.7%) and convex main thoracic (MT) zone (6.1%). The overall critical medial perforation rate was 0.9%. 33.3% occurred at convex MT and 22.2% occurred at transitional PT/MT zone. There were 39 anterior perforations (overall perforation rate of 2.0%). 43.6% occurred at transitional PT/MT zone, whereas 23.1% occurred at concave PT zone. The overall critical anterior perforation rate was 0.6%. 5/12 (41.7%) critical perforations occurred at concave PT zone, whereas four perforations occurred at the transitional PT/MT zone. There were only two symptomatic left medial grade 2 perforations (0.1%) resulting radiculopathy, occurring at the transitional main thoracic (MT)/Lumbar (L) zone.
CONCLUSION: Overall pedicle perforation rate was 8.4%. Highest rate of critical medial perforation was at the convex MT zone and the transitional PT/MT zone, whereas highest rate of critical anterior perforation was at the concave PT zone and the transitional PT/MT zone. The rate of symptomatic perforations was 0.1%.
OBJECTIVE: This study analyzed the flexibility of the unfused thoracic segments above the "potential upper instrumented vertebrae (UIV)" (T1-T12) and its compensatory ability in Lenke 5 and 6 curves using supine side bending (SSB) radiographs.
STUDY DESIGN: A retrospective study was used.
PATIENT SAMPLE: This study comprised 100 patients.
OUTCOME MEASURES: The ability of the unfused thoracic segments above the potential UIV, that is, T1-T12, to compensate in Lenke 5 and 6 curves was determined. We also analyzed postoperative radiological outcome of this cohort of patients with a minimum follow-up of 12 months.
METHODS: Right and left SSB were obtained. Right side bending (RSB) and left side bending (LSB) angles were measured from T1 to T12. Compensatory ability of thoracic segments was defined as the ability to return to neutral (center sacral vertical line [CSVL]) with the assumption of maximal correction of lumbar curve with a horizontal UIV. The Lenke 5 curves were classified as follows: (1) Lenke 5-ve (mobile): main thoracic Cobb angle <15° and (2) Lenke 5+ve (stiff): main thoracic Cobb angle 15.0°-24.9°. This study was self-funded with no conflict of interest.
RESULTS: There were 43 Lenke 5-ve, 31 Lenke 5+ve, and 26 Lenke 6 curves analyzed. For Lenke 5-ve, >70% of thoracic segments were able to compensate when UIV were at T1-T8 and T12 and >50% at T9-T11. For Lenke 5+ve, >70% at T1-T6 and T12, 61.3% at T7, 38.7% at T8, 3.2% at T9, 6.5% at T10, and 22.6% at T11 were able to compensate. For Lenke 6 curve, >70% at T1-T6, 69.2% at T7, 19.2% at T8, 7.7% at T9, 0% at T10, 3.8% at T11, and 34.6% at T12 were able to compensate. There was a significant difference between Lenke 5-ve versus Lenke 5+ve and Lenke 5-ve versus Lenke 6 from T8 to T11. There were no significance differences between Lenke 5+ve and Lenke 6 curves from T1 to T11.
CONCLUSIONS: The compensatory ability of the unfused thoracic segment of Lenke 5+ve curves was different from the Lenke 5-ve curves, and it demonstrated characteristics similar to the Lenke 6 curves.
METHODS: Computed tomography scans from 74 patients were retrospectively evaluated between January 2008 and December 2012. Pedicle perforations were classified by two types of grading systems. For medial, lateral, superior and inferior perforations: grade 0 - no violation; grade 1 - <2 mm; grade 2 - 2-4 mm and grade 3 - >4 mm. For anterior perforations: grade 0 - no violation; grade 1 - <4 mm; grade 2 - 4-6 mm and grade 3 - >6 mm.
RESULTS: There were 35 (47.3%) male and 39 (52.7%) female patients with a total 260 thoracic pedicle screws (T1-T6) analysed. There were 32 screw perforations which account to a perforation rate of 12.3% (11.2% grade 1, 0.7% grade 2 and 0.4% grade 3). None led to pedicle screw-related complications. The perforation rate was highest at T1 (33.3%, all grade 1 perforations), followed by T6 (14.5%) and T4 (14.0%).
CONCLUSION: Fluoroscopic guided percutaneous pedicle screws of the upper thoracic spine (T1-T6) are technically more demanding and carry potential risks of serious complications. Extra precautions need to be taken when fluoroscopic guided percutaneous pedicle screws are placed at T1 and T2 levels, due to high medial pedicular angulation and obstruction of lateral fluoroscopic images by the shoulder girdle and at T4-T6 levels, due to smaller pedicular width.
OBJECTIVE: The aim of this study was to assess the safety and pullout strength of medial, partial nonthreaded thoracic pedicle screws compared with conventional screws.
SUMMARY OF BACKGROUND DATA: The perforation rate of the pedicle screws has been reported as high as 41%. Nerve injury and irritation can result from the compression of malpositioned screw on neural structures.
METHODS: Ten fresh cadavers were studied. Screws, 5.0 and 6.0 mm, were inserted from T1 to T6 and T7 to T12, respectively. Pedicle perforations and fractures were recorded upon screw insertion and final positioning (nonthreaded portion facing medially) after a wide laminectomy. Pullout strength of novel and conventional screws were then tested using an Instron machine in an artificial bone substitute.
RESULTS: A total of 240 thoracic pedicle screws were inserted. Of them, 88.8% (213 screws) were fully contained during screw insertion. There were 5.0% (12 screws) grade 1 medial perforations and 6.2% (15 screws) grade 1 lateral perforations during screw insertion. Upon final positioning, 93.8% (225 screws) were fully contained. All grade 1 medial perforations, which occurred during insertion, were converted to grade 0. No dural or nerve root injuries occurred. Pedicle split fractures were noted in 6.7% (16 screws). The use of medial, partial nonthreaded screws reduced the overall perforation rate from 11.2% to 6.2%. The mean pullout load for the 5 mm fully threaded screw versus medial, partial nonthreaded was 1419.3±106.1 N (1275.8-1538.8 N) and 1336.6±44.2 N (1293.0-1405.1 N) respectively, whereas 6 mm pullout load averaged 2126.0±134.8 N (1986.3-2338.3 N) and 2036.5±210.0 N (1818.4-2355.9 N). The difference was not statistically significant.
CONCLUSIONS: The use of medial, partial nonthreaded pedicle screws reduced the medial perforation rate from 5.0% to 0%; however, the pullout strength was not significantly reduced. The use of this novel screw can potentially reduce the incidence of nerve injury or irritation after medial pedicle perforations.
OBJECTIVE: To investigate the accuracy and safety of pedicle screws placed in adolescent idiopathic scoliosis (AIS) patients.
SUMMARY OF BACKGROUND DATA: The reported pedicle screws perforation rates for corrective AIS surgery vary widely from 1.2% to 65.0%. Knowledge regarding the safety of pedicle screws in scoliosis surgery is very important in preventing complications.
METHODS: This study investigates the accuracy and safety of pedicle screws placed in 140 AIS patients. CT scans were used to assess the perforations that were classified according to Rao et al (2002): grade 0, grade 1 (<2 mm), grade 2 (2-4 mm), and grade 3 (>4 mm). Anterior perforations were classified into grade 0, grade 1 (<4 mm), grade 2 (4-6 mm), and grade 3 (>6 mm). Grade 2 and 3 (excluding lateral grade 2 and 3 perforation over thoracic vertebrae) were considered as critical perforations.
RESULTS: A total of 2020 pedicle screws from 140 patients were analyzed. The overall total perforation rate was 20.3% (410 screws) with 8.2% (166 screws) grade 1, 2.9% (58 screws) grade 2 and 9.2% (186 screws) grade 3 perforations. Majority of the perforations was because of lateral perforation occurring over the thoracic region, as a result of application of extrapedicular screws at this region. When the lateral perforations of the thoracic region were excluded, the perforation rate was 6.4% (129 screws), grade 2, 1.4% (28 screws) and grade 3, 0.8% (16 screws). There were only two symptomatic left medial grade 2 perforations: one screw at T12 presented with postoperative iliac crest numbness and another screw at L2 presented with radicular pain that subsided with conservative treatment. There were six anterior perforations abutting the right lung, four anterior perforations abutting the aorta, two anterior perforations abutting the esophagus, and one abutting the trachea was noted.
CONCLUSION: Pedicle screws insertion in AIS has a total perforation rate of 20.3%. After exclusion of lateral thoracic perforations, the overall perforation rate was 8.6% with a critical perforation rate of 2.2% (44/2020). The rate of symptomatic screw perforation leading to radicular symptoms was 0.1%. There was no spinal cord, aortic, esophageal, or lung injuries caused by malpositioned screws in this study.
LEVEL OF EVIDENCE: 4.
OBJECTIVE: To report the successful rehabilitation and the training progress of an elite high performance martial art exponent after selective thoracic fusion for Adolescent Idiopathic Scoliosis (AIS).
SUMMARY OF BACKGROUND DATA: Posterior spinal fusion for AIS will result in loss of spinal flexibility. The process of rehabilitation after posterior spinal fusion for AIS remains controversial and there are few reports of return to elite sports performance after posterior spinal fusion for AIS.
METHODS: We report a case of a 25-year-old lady who was a national Wu Shu exponent. She was a Taolu (Exhibition) exponent. She underwent Selective Thoracic Fusion (T4 to T12) using alternate level pedicle screw placement augmented with autogenous local bone graft in June 2014. She commenced her training at 3-month postsurgery and the intensity of her training was increased after 6 months postsurgery. We followed her up to 2 years postsurgery and showed no instrumentation failure or lost of correction.
RESULTS: After selective thoracic fusion, her training process consisted of mainly speed training, core strengthening, limb strengthening, and flexibility exercises. At 17 months of postoperation, she participated in 13th World Wu Shu Championship 2015 and won the silver medal.
CONCLUSION: Return to elite high-performance martial arts sports was possible after selective thoracic fusion for AIS. The accelerated and intensive training regime did not lead to any instrumentation failure and complications.
LEVEL OF EVIDENCE: 2.