3-dimensional Correction Research Articles

Biomechanical Computational Study of Pedicle Screw Position and Density in Adolescent Idiopathic Scoliosis Instrumentation.

Computer simulation of adolescent idiopathic scoliosis instrumentation. To test the hypothesis that different screw densities would result in different apical vertebral rotation (AVR) corrections and bone-screw forces in adolescent idiopathic scoliosis instrumentation. The "Minimize Implants Maximize Outcomes" Clinical Trial revealed that the use of more versus fewer screws resulted in similar coronal plane correction for Lenke 1A curves. However, the biomechanical impact of screw density on transverse plane correction is still unclear. Further investigation is needed to determine if and how transverse plane correction is correlated with screw density. We simulated apical vertebral derotation after segmental translation using patient-specific computer models of 30 patients from the "Minimize Implants Maximize Outcomes" Trial. For each case, 10 alternative screw patterns were tested with overall densities ranging between 1.2 and 2 screws per level fused, and local density at the 3 apical levels ranging between 0.7 and 2 (total: 600 simulations). Main thoracic (MT) Cobb angle, thoracic kyphosis (TK), AVR, and bone-screw forces were computed and compared. The presenting MT (62 ± 11°; range: 45° to 86°), TK (27 ± 20°; -5° to 81°), and AVR (14±7°; -2° to 25°) were corrected through segmental translation to 22 ± 7° (10° to 41°), 26 ± 5° (18° to 45°), and 14 ± 7° (-4° to 26°). After apical vertebral derotation, they became 16 ± 8° (1° to 41°), 24 ± 4° (13° to 40°), and 4 ± 5° (-12° to 18°). There was no significant difference in MT among screw patterns; higher screw density had lower bone-screw forces ( P < 0.05). The apical vertebral derotation maneuver reduced AVR by an average of 70%, positively correlated with apical screw density ( r = 0.825, P < 0.05). There was no significant difference in TK. Screw density had no significant effect on 3-dimensional correction through the primary segmental translation maneuver. Transverse plane correction through subsequent apical vertebral derotation was positively correlated with screw density at the apical levels ( r = 0.825, P < 0.05). Bone-screw forces were negatively correlated with overall screw density ( P < 0.05).

Dual Growing Rods Combined With the Apical Convex Control Pedicle Screw Technique Versus Traditional Dual Growing Rods for the Surgical Treatment of Early-Onset Scoliosis: A Case-Matched 2-Year Study.

Combination of apical control convex pedicle screws (ACPS) with traditional dual growing rods (TDGRs) had better apex control ability for early-onset scoliosis (EOS); however, there is a paucity of studies on the ACPS technique. To compare 3-dimensional deformity correction parameters and complications between the apical control technique (DGR + ACPS) and TDGR in the treatment of EOS. A retrospective case-match analysis consisting of 12 cases of EOS treated with the DGR + ACPS technique (group A) from 2010 to 2020, and matched with TDGR case (group B) at a ratio of 1:1 by age, sex, curve type, major curve degree, and apical vertebral translation (AVT). Clinical assessment and radiological parameters were measured and compared. Demographic characteristics, preoperative main curve, and AVT were comparable between groups. The correction ability of the main curve, AVT, and apex vertebral rotation were better in group A at index surgery ( P < .05). The increase in T1-S1 and T1-T12 height was large in group A at index surgery ( P = .011, P = .074). The annual increase in spinal height was slower in group A, but without significant difference. The surgical time and estimated blood loss were comparable. Six complications occurred in group A, and 10 occurred in group B. In this preliminary study, ACPS seems to provide better correction of apex deformity, while attaining the comparable spinal height at 2-year follow-up. Larger cases and longer follow-up are needed to achieve reproducible and optimal results.

5.5-mm Cobalt-Chrome vs 6-mm Titanium Alloy Rods in Surgical Treatment of Lenke 1 Adolescent Idiopathic Scoliosis With High-Density Pedicle Screws and Direct Vertebral Rotation on Differently Shaped Rods: A Retrospective Comparative Cohort Study.

The gold standard of surgical treatment of adolescent idiopathic scoliosis (AIS) consists of a posterior approach requiring complex 3-dimensional correction with multisegmental pedicle screws and 2 contoured rods. The substantial corrective forces and the ability of the rod to withstand these forces rely on its biomechanical properties. The aim of this study is to compare outcomes of 5.5-mm cobalt-chrome (CoCr) and 6-mm titanium alloy (TiAl) rods in surgical correction in Lenke 1 AIS patients. TiAl has greater elasticity, which may facilitate the correction maneuver, whereas the stiffness of CoCr may result in stronger correction forces. The literature provides no clear indications about which rod may allow better correction and safety. A total of 64 consecutive patients (30 CoCr vs 34 TiAl) with Lenke 1 AIS <100°, with 2 years minimum follow-up, requiring correction and posterior fusion at our institution were included. The primary outcome measure was coronal and sagittal correction and loss of correction at 2-year follow-up. Secondary outcome measures compared peri- and postoperative complications. The mean coronal correction was higher in the CoCr group: -73.6% ± 7.4 vs -65.5% ± 11 (P = 0.001). Mean T5-T12 kyphosis did not change significantly after surgery. In patients with hypokyphosis (<10°), an improvement in thoracic kyphosis was observed in both groups, but the improvement was significantly higher in the TiAl group (P = 0.038). In patients with hyperkyphosis (>40°), a similar reduction in thoracic kyphosis was observed in both groups. At follow-up, no coronal correction loss occurred. The sagittal correction loss was slight (0.5° ± 1.5 for the CoCr group, 1.5° ± 3 for the TiAl group) but statistically higher in the TiAl group (P = 0.032). There were no mechanical complications. One revision was required for infection in the CoCr group. In this series of Lenke 1 AIS, with the limitations of the study, 5.5-mm CoCr rods have provided better correction in the coronal plane than 6-mm TiAl rods. However, TiAl rods have been found to be associated with higher increase of thoracic kyphosis in hypokyphotic curves, although the clinical relevance of this finding could be questionable. This article provides surgeons with more information regarding rod material options when correcting Lenke 1 AIS.

Dual-Rod Instrumentation Via the Anterior Approach for Thoracolumbar and Lumbar Adolescent Idiopathic Scoliosis

Background: Posterior spinal fusion with pedicle screw instrumentation is currently the standard technique for spinal surgery. However, the anterior approach remains useful for thoracolumbar and lumbar (TL/L) lesions, such as in adolescent idiopathic scoliosis (AIS) 1–4 and spinal injuries 5,6 . We previously documented that long-term radiographic findings and clinical measures were satisfactory in patients with TL/L AIS treated with anterior dual-rod instrumentation 1 . Description: This surgical technique is indicated for single TL/L (Lenke 5) curves and is performed with use of extrapleural retroperitoneal approaches. The extrapleural cavity is connected to the retroperitoneal space by diaphragmatic transection. The lateral aspect of the vertebral bodies is exposed by retracting the psoas major muscle posteriorly from the intervertebral discs. Segmental vascular bundles are divided with coagulation and/or ligation. Care should be taken to reflect the psoas in its entirety and avoid an intramuscular approach to prevent bleeding injury to nerves, including the femoral, ilioinguinal, and genitofemoral nerves, as well as ureteral injury. After the intervertebral discs and cartilage plates are removed to the vertebral end plates, 2 screws are inserted in each vertebral body through a vertebral staple 1,4 . The anterior rod is then placed in the screw heads and rotated anteriorly, providing 3-dimensional correction of kyphotic deformities with lordosis production 1,4 . After the posterior rod is applied in the same manner as the anterior rod, compression forces are applied between the screws to correct scoliosis 1,4 . The compression force is first applied to the posterior rod so that kyphosis can be corrected more effectively 1,4 . Alternatives: Posterior pedicle screw instrumentation techniques are widely utilized for TL/L AIS curve correction. However, anterior techniques have frequently also been applied to the curve. Dwyer et al. 7 first reported the use of anterior spinal fusion (ASF) with a single braided cable connecting vertebral screws for the treatment of TL/L AIS, and Zielke et al. 8 modified that procedure by replacing the cable with a threaded rod. Although these instrumentation techniques and other single anterior rod techniques such as the Texas Scottish Rite Hospital System effectively correct scoliosis in the coronal plane and improve vertebral derotation 1,9 , poor sagittal and rotational plane deformity correction, implant weakness, and high incidence of pseudarthrosis remain unresolved issues 1 . Rationale: The fundamental advantages of the anterior approach in dual-rod instrumentation are the ability to achieve 3-dimensional correction with extremely low rates of pseudarthrosis and implant failure 1,10–12 . Furthermore, the fusion is expected to include fewer motion segments than with posterior systems (usually 1 level less distally and proximally). However, low skeletal maturity and a TL/L to thoracic Cobb ratio of &lt;1.25 appeared to be important factors for postoperative curve progression of the thoracic coronal deformity following ASF for the treatment of Lenke 5 curves 1,13 . In addition, subjacent disc wedging may occur when the subjacent disc is nearly parallel before surgery 1,14 . Expected Outcomes: The described technique is expected to provide 3-dimensional spinal correction. In a previous study, 30 patients with Lenke 5 AIS were followed for a mean of 17 years 1 . The mean TL/L Cobb angle correction rate and correction loss were 79.8% and 3.4°, respectively, at the time of the latest follow-up 1 . The average percent of predicted forced vital capacity and of forced expiratory volume in 1 second were 91.8% and 81.8%, respectively 1 . The average total score on the Scoliosis Research Society-30 outcome instrument was 4.21. No instrumentation failure, pseudarthrosis, or clinically relevant neurovascular complications were observed 1 . Important Tips: This technique is applicable to Lenke 5 AIS curves. However, the anterior approach can also be utilized for other TL/L lesions.The anterior procedure is accomplished via extrapleural retroperitoneal approaches with diaphragmatic transection.Care should be taken to reflect the psoas in its entirety and avoid an intramuscular approach to prevent bleeding and nerve and ureteral injuries. Acronyms &amp; Abbreviations: SRS-30 = Scoliosis Research Society-30

Lapidus with 1st Metatarsal-Intermediate Cuneiform Fixation Improves Rotational Correction of Hallux Valgus

Category: Bunion Introduction/Purpose: The modified Lapidus procedure offers effective correction of the triplanar deformity of hallux valgus; however, complications such as nonunion and recurrence range up to 15% when using a crossing lag screw fixation technique. An alternative form of fixation using a dorsomedial plate and first metatarsal-intermediate cuneiform (1MT-IC) screw has been proposed. This construct may reduce complication rates, facilitate earlier weightbearing and maintain 3-dimensional correction, especially rotation of the first ray. We investigated single-surgeon Lapidus patient cohorts utilizing cross screws (CS) versus plate and 1MT-IC screw (PS) fixation to compare patient reported outcomes, radiologic parameters on pre- and postoperative weightbearing CT (WBCT) and complications. We hypothesized that patients undergoing PS fixation would experience improved correction of first ray pronation. Methods: This single-center, IRB-approved retrospective study identified all patients who underwent first tarsometatarsal joint arthrodesis for hallux valgus by a single surgeon and divided them by CS or PS fixation. Patients were minimum 18 years old with at least 12 months of follow-up. Revision forefoot surgeries, concomitant flatfoot reconstruction or ankle replacement, and patients with history of rheumatoid arthritis or gout were excluded. PROMIS scores in six key domains were compared between groups both preoperatively and at one year postoperatively. Radiographic assessment of hallux valgus angle (HVA) and intermetatarsal angle (IMA) were performed on pre- and postoperative XR. Pronation of the first ray was measured on WBCT using the validated triplanar angle of pronation. Clinical notes were reviewed for complications and reoperations. The PS group began weightbearing at an average 3.6 weeks versus 6 weeks the PS group. Results: We compared 44 patients who underwent Lapidus with PS and 43 with CS fixation. The age, BMI and gender distribution in the two groups were similar. Both groups had significant improvement in HVA and IMA following Lapidus, (p&lt;0.001), with no difference between groups. Average first ray pronation among PS patients was corrected to 26.0 degrees (from 36.6 degrees preoperatively), which was lower than the final pronation of 30.5 degrees in the CS group, (p&lt;0.001). Both cohorts experienced improvement in PROMIS physical function, pain interference, pain intensity and global physical function. There were no differences in PROMIS score improvements between the cohorts. Weightbearing commenced earlier in the PS group without increased complications. Conclusion: The plate and 1MT-IC screw technique for Lapidus fixation has been described to provide better biomechanical stability and potentially maintain the desired hallux valgus correction by spanning the intermetatarsal joint. Prior studies have reported durable radiographic IMA correction with low nonunion rates. We found similar patient-reported outcomes and rates of complications compared with a group of cross-screw fixation patients. However, there was a significant difference in final pronation of the first ray, 26 vs 31 degrees, observed by weightbearing CT. Earlier weightbearing and improved rotational correction are advantages associated with PS fixation of Lapidus bunionectomy.

A FLEXIBLE AND ROBUST 3D COORDINATE MEASUREMENT SYSTEM BASED ON WHITE LIGHT INTERFEROMETRY FOR DEVIATION MEASUREMENTS ON SWISS-TYPE TURNING MACHINES

The calibration of machine tools or industrial robots needs high precision 3-dimensional coordinate measurements. Common available systems still have the need of ambitious and time extensive processes to fulfill the requested requirements. Therefore there is a strong request for fully automated systems that allow an autonomous and easy to handle procedure for 3D volumetric deviation measurements. This exactly is the intension of the here presented 3D Coordinate Measurement System. The so called µ-GPS System is based on reliable white light interferometer and robust technology. The 3D coordinates are determined via trilateration from three measured distances like it is known from the global GPS. Mainly two parts, the sensor unit (transceiver unit) including the emitter and the reference base (three cat’s-eyes) which includes the three reflectors are mounted in the workspace of the machine. A model to evaluate the signals was developed which allows in combination with a 3-dimensional failure correction a 3D accuracy of more than 5 microns. This application will be the base for an exemplary and fully automated calibration process of Swiss-type turning machines. As these machines are used in high volume manufacturing for precision parts, they need to be assembled and calibrated very accurately. For the long term stability the µ-GPS System can be easily assembled in the Swiss-type turning machine so that thermal deviations and abrasion can be measured and compensated in the control. The robust and easy handling of the µ-GPS System later allows an expansion of the showcase to robots and other machine tools.

Three-Dimensional Correction of Hallux Valgus Deformity: A Novel Technique

Background: Minimally invasive techniques for forefoot surgery are increasingly used nowadays with short operative time and smaller incisions allowing early rehabilitation. Consequently, the purpose of this study was to evaluate a novel technique for 3-dimensional correction of hallux valgus deformity using small incisions. Materials and methods: A single-center, prospective study was conducted from February 2016 to February 2019. The study included a total of 36 feet in 34 patients with hallux valgus deformity treated with soft tissue release combined with osteotomy of the first metatarsal base with correction of angular, rotational deformities of the hallux and fixation by transverse pinning to the second metatarsal. Patients were assessed radiographically for union and measurements as well as clinically using the “The American Orthopedic Foot and Ankle Society (AOFAS)” for functional assessment. Results: Union was achieved in all cases. Hallux valgus angle improved from a mean of 40±5.9 degrees to a mean of 9.1±2.3 degrees (P&lt;0.001). Intermetatarsal angle improved from a mean of 17.5±2.1 degrees to a mean of 6.1±1.5 degrees (P&lt;0.001). At the final follow-up period (2 y), the mean hallux valgus angle was 10.9±2.8 degrees (P&lt;0.001) and the mean intermetatarsal angle was 7±1.7 degrees (P&lt;0.001). Conclusion: This technique yielded good radiographic and functional outcomes and can be a viable option in management of mild, moderate, and severe cases of hallux valgus deformity. Level of Evidence: Level IV, Therapeutic study.

Analysis of Shortening and Elevation of the First Ray With Instrumented Triplane First Tarsometatarsal Arthrodesis.

Background:The Lapidus procedure using planar saw resection has often been criticized for complications related to excessive shortening and elevation of the first ray. The goal of this study was to assess the amount of shortening that occurs when using a cutting guide for controlled saw resection of the first tarsometatarsal (TMT) joint surfaces, along with assessment of deformity correction in all 3 anatomic planes.Methods:A prospective multicenter study with IRB approval included 35 hallux valgus subjects evaluated at baseline and 6 months following instrumented triplane first TMT arthrodesis without lesser metatarsal osteotomies.Results:The average first ray bone segment length loss was 3.1 mm (95% confidence interval [CI] 2.4-3.7) in the anteroposterior (AP) radiographic assessment and 2.4 mm (95% CI 1.7-3.1) in the sagittal plane. The mean preoperative radiographic measurements were 1.7 degrees (dorsiflexion) for sagittal plane angle, 13.8 degrees for intermetatarsal angle (IMA), and 5.1 for tibial sesamoid position (TSP). Improvements were seen postoperatively for all measures with a mean difference of –0.2 degrees (95% CI –1.0 to 0.6) for sagittal plane angle, –9.2 degrees (95% CI –10.1 to –8.3 degrees) for IMA, and –3.5 (95% CI –4.0 to –3.1) for TSP. Five of the patients reported lesser metatarsal pain preoperatively, and no patients complained of lesser metatarsalgia at 6-month follow-up.Conclusions:Minimal length loss of the first ray can be expected following instrumented triplane TMT arthrodesis while achieving full 3-dimensional deformity correction and reducing the risk of lesser metatarsalgia.Level of Evidence:Level II, prospective comparative study.

Accuracy and Early Clinical Outcome After 3-Dimensional Correction of Distal Radius Intra-Articular Malunions Using Patient-Specific Instruments

To investigate the residual articular incongruity on computed tomography image data and the early clinical outcome of 3-dimensional planned and navigated intra-articular osteotomies of the distal radius. We conducted a retrospective analysis of intra-articular osteotomies executed between 2008 and 2016. We identified 37 patients (aged 26-73 years) and performed a combined intra-articular and extra-articular osteotomy on 20 patients. A preoperative 3-dimensional plan with the superimposed bone of the contralateral healthy side was performed in each case to analyze and execute the osteotomy by intraoperative navigation. The residual articular incongruity was assessed by quantification of the maximal stepoff in the coronal or sagittal computed tomography scans. Clinical outcome, including range of motion, grip strength, and return to work, was assessed after a minimum follow-up of 12 months and compared with preoperative measurements. On average, the preoperative intra-articular stepoff was 2.5 mm (±0.6 mm; range, 1.4-4.2 mm) and was significantly reduced to 0.8 mm (±0.2 mm) after surgery. After surgery, 30 patients had a stepoff less than 1 mm; in 7, a stepoff of 1.1 to 1.4 mm was measured. After 1 year, 22 had no pain, 9 had slight pain during heavy work, and 5 had moderate pain with no improvement compared with their preoperative status, although wrist strength and range of motion improved in all 37 patients. One patient underwent a secondary radioscapholunate arthrodeses owing to persistent pain despite a congruent joint with a small residual intra-articular stepoff (0.6 mm). Intra-articular osteotomies of the distal radius treated by 3-dimensional preoperative planning and patient-specific guides are an accurate technique to reduce articular incongruity to an average stepoff of 0.8 mm (range, 0.3-1.4 mm). The early clinical outcomes demonstrated overall reduction in pain and improvement of range of motion and grip strength in 36 of 37 patients. Therapeutic IV.

Effect on Foot Width With Triplanar Tarsometatarsal Arthrodesis for Hallux Valgus.

Background:Foot width reduction is a desirable cosmetic and functional outcome for patients with hallux valgus. Triplanar first tarsometatarsal (TMT) arthrodesis could achieve this goal by 3-dimensional correction of the deformity. The aim of this study was to evaluate changes in bony and soft tissue width in patients undergoing triplanar first TMT arthrodesis.Methods:After receiving Institutional Review Board approval, charts were retrospectively reviewed for patients undergoing triplanar first TMT arthrodesis for hallux valgus at 4 institutions between 2016 and 2019. Patients who underwent concomitant first metatarsal head osteotomies (eg, Silver or Chevron) or fifth metatarsal osteotomies were excluded. Preoperative and postoperative anteroposterior weightbearing radiographs were compared to evaluate for changes in bony and soft tissue width. One hundred forty-eight feet from 144 patients (48.1 ± 15.7 years, 92.5% female) met inclusion criteria.Results:Preoperative osseous foot width was 96.2 mm, compared to 85.8 mm postoperatively (P < .001). Preoperative soft tissue width was 106.6 mm, compared to 99.3 mm postoperatively (P < .001). Postoperatively, patients had an average 10.4 ± 4.0 mm reduction (10.8% reduction) in osseous width and average 7.3 ± 4.0 mm reduction (6.8% reduction) in soft tissue width.Conclusions:Triplanar first TMT arthrodesis reduced both osseous and soft tissue foot width, providing a desirable cosmetic and functional outcome for patients with hallux valgus. Future studies are needed to determine if patient satisfaction and outcome measures correlate with reductions in foot width. Level of evidence: Level III, retrospective comparative study

Posterior Spinal Fusion With Multilevel Posterolateral Convex Disc Releases for the Treatment of Severe Thoracolumbar Scoliosis.

Severe, rigid thoracolumbar scoliosis presents a surgical challenge to achieve 3-dimensional correction, maximize distal motion segments, and avoid operative morbidity conferred by combined anterior-posterior approaches or 3-column osteotomies. We present a new approach for releasing these curves, using multilevel posterolateral convex disc release (PCDR) and posterior instrumented fusion. There were 3 adults and 1 adolescent (mean age, 31.8 years; 2 females) with severe progressive thoracic and transforaminal lumbar (major) idiopathic scoliosis (IS) who were treated with 3-level PCDR, multiple posterior column osteotomies, and posterior instrumented thoracolumbar fusion with all-pedicle screw constructs. Restoration of global coronal and sagittal alignment was achieved for all patients (minimum 2-year follow-up). Lowest instrumented vertebra (LIV) was L4 in 2 patients and L3 in the remaining 2. All except 1 were fused to the lower end vertebra. Postoperatively, mean thoracolumbar curve was reduced from 77.3° (range, 69°-91°) to 21.8° (72%Δ), LIV tilt decreased from 26.8° to 8.3°, and LIV translation improved (2.5-1.2 cm; 58%Δ), whereas lumbar lordosis remained unchanged. Average central sacral vertical line shift measured via C7 sagittal vertical axis changed from 1.4 to -0.7 cm. There were no complications except for dysesthesias in the lower extremity on the side of the PCDR in 1 patient, which resolved after 3 months. Severe thoracolumbar IS presents a surgical challenge to achieve 3-dimensional correction, minimize fusion levels, and avoid procedural morbidity. PCDR is a novel technique that may facilitate this correction with minimal procedure-related morbidity.

TREATMENT OF SEVERE SPINAL DEFORMATIONS IN CHILDREN WITH IDIOPATHIC SCOLIOSIS USING HALO-GRAVITY TRACTION

The aim: To chose the best way treatment and achievement of 3-dimensional spinal correction in order to maximize its parameters to the physiological norms is a choice of the optimal surgical severe scoliotic spinal deformity correction technology. Materials and methods: Performed surgical treatments to 60 children of two patient’s groups, that were under surgical treatment for severe scoliotic spinal deformations with preliminary used halo-gravity traction and one-step correction; to establish an effective and safe protocol of the treatment for children with severe scoliotic spinal deformations (&gt;100°). The results comparative analysis of 60 patients with severe scoliotic spinal deformations, with a two-step surgery treatments (first step – halo-gravity traction and second step – correcting spinal instrumentation) and patients with one-step correction. Patients were divided into 2 groups with 30 children in each of them. The first group treated with preoperatively HGT (halo-gravity traction) and after that a spinal instrumentation together with osteotomies (3-4 levels by Ponte; VCR (vertebral column resection) osteotomy 1 level) were performed. The second group – performed one-step spinal instrumentation with osteotomies (3-4 levels by Ponte; VCR osteotomy 1 level). Results: One-step implanted construction in children with severe scoliotic spinal deformations, compare to HGT treatment that were carried out in stages – is increasing the danger of neurological deficiency by 17%, HGT allows to make more corrections and to adjust spinal cord for the next correction treatment. . Conclusions: Halo-gravity traction as a first stage of severe scoliotic spinal deformations treatment allows to increase the mobility of the vertebral column and to adjust spinal cord step by step for the next correction treatment.

Periapical-dropout Screws Strategy For 3-Dimensional Correction of Lenke 1 Adolescent Idiopathic Scoliosis in Patients Treated by Posterior Spinal Fusion.

This was a single-center, retrospective study. The objective of this study was to compare periapical-dropout screws strategy (PDSS) with traditional-multilevel pedicle screws strategy (TMSS) for 3-plane correction of Lenke 1 adolescent idiopathic scoliosis deformity. There are limited data in 3-plane correction and the optimal pedicle screw (PS) configuration for Lenke 1 adolescent idiopathic scoliosis surgery. Sixty-one consecutive patients with Lenke 1 curves (range: 50-80 degrees), undergoing single-stage posterior spinal fusion with PS fixation, were included. Patients with a minimum follow-up of 1 year were divided into 2 groups according to PS strategy. The PDSS group included 33 patients with PS placement bilaterally at both ends and apex of the construct. The TMSS group included 28 patients with conventional PS placement. Baseline, immediate, and last follow-up demographic, radiographic, and clinical outcomes were analyzed. Radiographic outcomes were assessed in axial (using rib index and apical vertebral rotation using Raimondi ruler and Upasani methods), coronal, and sagittal planes. The implant costs were also evaluated. There were no differences in demographic, preoperative radiographic parameters and levels fused. The number of PSs per level fused was significantly lower in the PDSS group (1.3 vs. 1.4; P=0.0002). At last follow-up, major Cobb correction averaged 79% for the PDSS group and 69.5% for the TMSS group (P=0.001). T2-T12 kyphosis angle changes were 1 degree in the PDSS group and -2.5 degrees in the TMSS group (P=0.35). Rib index correction was 28.2% for the PDSS group and 17.7% for the TMSS group (P=0.02). Upasani grade apical vertebral rotation was significantly better in the PDSS group (0.7 vs. 1.4; P=0.0001). Clinical outcomes evaluated by Scoliosis Research Society-30 scores were similar in both groups. Total implant costs were significantly lower in the PDSS group ($16,852 vs. $18,926; P<0.001). The PDSS construct provides better deformity correction in all 3 planes and helps decrease implant costs compared with the TMSS construct. Thus, the PDSS construct can be considered as a rational strategy and cost-effective technique when treating moderate Lenke 1 curves with posterior spinal fusion.

Is Anterior Release Obsolete or Does It Play a Role in Contemporary Adolescent Idiopathic Scoliosis Surgery? A Matched Pair Analysis.

A retrospective analysis of a prospectively collected database was performed. The purpose of this study is to compare 3-dimensional correction associated with the anterior release (AR) and contemporary posterior instrumentation versus posterior-only surgery. The role of AR as a tool in the treatment of adolescent idiopathic scoliosis (AIS) has seen a decline with the popularization of thoracic pedicle screw instrumentation. Five surgeons were queried for all surgical thoracic AIS cases from 2003 to 2010 treated with thoracoscopic AR/fusion and contemporary posterior instrumentation and fusion and thoracic pedicle screw instrumentation (>80% screws) with 2-year follow-up. These cases were then matched with posterior spinal fusion only cases from a multicenter prospective database. The 2 groups were matched on the basis of major curve magnitude within 5 degrees, T5-T12 kyphosis within 9 degrees, and angle of trunk rotation within 9 degrees. Radiographic and clinical parameters were compared for the 2 groups. Continuous variables were analyzed with analysis of variance and categorical dependent variables with the χ test. A total of 47 cases of AR were matched to 47 (1:1 match) posterior spinal fusion cases. Preoperative parameters were similar between groups (P>0.05). Postoperatively, AR cases had a lower major curve (20 vs. 25 degrees, P=0.034; 72% vs. 66% correction, P=0.037). T5-T12 kyphosis was greater in the AR cases (26 vs. 20 degrees; P=0.005). The angle of trunk rotation was similar for the groups. Anchor density was lower in the AR group (1.6 vs. 1.9; P<0.0001). There were 3 complications associated with the AR: 1 pneumothorax and 2 conversions to minithoracotomies for failure to maintain single lung ventilation. AR improves coronal and sagittal plane correction in contemporary AIS surgery with a satisfactory complication profile with less pedicle screw density required for clinically similar corrections. A further prospective study on the benefits of AR may help define specific indications.

Correction of Adolescent Idiopathic Scoliosis Using a Convex Pedicle Screw Technique: A Novel Technique for Deformity Correction.

We describe our convex segmental pedicle screw technique for the treatment of adolescent idiopathic scoliosis. We developed this technique to achieve optimum 3-dimensional deformity correction while reducing the surgical risks of an inherently dangerous procedure. The surgery involves a wide posterior subperiosteal exposure across the deformity levels to the tips of the transverse processes. Posterior releases are performed through facetectomies. Pedicle screws are placed using a freehand technique based on anatomical landmarks. Adequate screw positioning is assessed with an image intensifier before rod engagement. Segmental pedicle screws are placed across the convexity of each curve included in the fusion. Proximal and distal fixation of the rods on the contralateral side is performed across 2 pedicle screw anchors. We use titanium rods bilaterally. Curve correction is done using the convex pedicle screws by applying segmental vertebral translation and derotation starting with the main thoracic curve followed by the lumbar curve. Segmental compression or distraction is performed at the proximal and distal ends of the construct to level the end vertebrae included in the fusion. Maximum correction of the main thoracic scoliosis is done, whereas the lumbar scoliosis (which is usually more flexible) is corrected to the point that results in a globally balanced spine in the coronal plane. The rod attached on the convex side of the main thoracic scoliosis is overbent to restore thoracic kyphosis, and the aim is always to achieve regional and global sagittal balance. An interfacetal, intertransverse, and interlaminar fusion is performed with use of locally harvested bone supplemented by allograft bone. With previous techniques, the use of bilateral segmental pedicle screw fixation has been advocated as a requirement to achieve adequate deformity correction in patients with adolescent idiopathic scoliosis. This technique is associated with low risks of neurological and vascular complications because the screws are placed at the convex pedicles, away from the spinal cord/cauda equina and the aorta. The use of far fewer pedicle screws compared with previous techniques reduces surgical time and blood loss, which is related to lower postoperative morbidity. It may also decrease the risk of deep wound infection, which is associated with the number of implants used. Low implant density (1.2, with a density of 2 representing placement of pedicle screws bilaterally at every instrumented segment) with our technique can achieve satisfactory scoliosis correction, improved thoracic kyphosis, and normal global sagittal balance. Our use of this technique has resulted in excellent patient satisfaction and functional outcomes with no neurological complications or intraoperative neuromonitoring events, deep wound infections, detected nonunions, or need for revision surgery.

Choice of Rods in Surgical Treatment of Adolescent Idiopathic Scoliosis: What Are the Clinical Implications of Biomechanical Properties? – A Review of the Literature

The surgical treatment of adolescent idiopathic scoliosis (AIS) involves 3-dimensional curve correction with multisegmental pedicle screws attached to contoured bilateral rods. The substantial corrective forces exert a high level of stress on the rods, and the ability of the rod to withstand these forces without undergoing permanent deformation relies on its biomechanical properties. These properties, in turn, are dependent on the material, diameter, and shape of the rod. The surgical treatment of AIS is characterized by the requirement for a special biomechanical profile that may differ substantially from what is needed for adult deformity surgery. This overview summarizes the current knowledge of rod biomechanics in frequently used rod constructs, with a particular focus on translational research between biomechanical studies and clinical applicability in AIS patients.

Consensus Recommendations for Treatment Strategies in Indians Using Botulinum Toxin and Hyaluronic Acid Fillers.

Background:Indians constitute one of the largest population groups in the world. Facial anthropometry, morphology, and age-related changes in Indians differ from those of other ethnic groups, necessitating a good understanding of their facial structure and the required aesthetic treatment strategies. However, published recommendations specific to Indians are few, particularly regarding combination treatment.Methods:The Indian Facial Aesthetics Expert Group (19 dermatologists, plastic surgeons, and aesthetic physicians with a mean 15.5 years’ aesthetic treatment experience) met to develop consensus recommendations for the cosmetic facial use of botulinum toxin and hyaluronic acid fillers, alone and in combination, in Indians. Treatment strategies and dosage recommendations (agreed by ≥ 75% of the group) were based on results of a premeeting survey, peer-reviewed literature, and the experts’ clinical experience.Results:The need for combination treatment increases with age. Tear trough deficiency is the most common midface indication in Indian women aged 20–40 years. In older women, malar volume loss and jowls are the most common aesthetic concerns. Excess medial soft tissue on a relatively smaller midface precedes age-related sagging. Hence, in older Indians, fillers should be used peripherally to achieve lift and conservatively in the medial zones to avoid adding bulk medially. The shorter, wider lower face requires 3-dimensional correction, including chin augmentation, to achieve increased facial height and the oval shape desired by most Indian women.Conclusions:These recommendations give physicians treating Indians worldwide a better understanding of their unique facial characteristics and provide treatment strategies to achieve optimal aesthetic outcomes.

Quantifying the Effect of 3T Magnetic Resonance Imaging Residual System Distortions and Patient-Induced Susceptibility Distortions on Radiation Therapy Treatment Planning for Prostate Cancer

Toinvestigate the effect of magnetic resonance system- and patient-induced susceptibility distortions from a 3T scanner on dose distributions for prostate cancers. Combined displacement fields from the residual system and patient-induced susceptibility distortions were used to distort 17 prostate patient CT images. VMAT dose plans were initially optimized on distorted CT images and the plan parameters transferred to the original patient CT images to calculate a new dose distribution. Maximum residual mean distortions of 3.19mm at a radial distance of 25cm and maximum mean patient-induced susceptibility shifts of 5.8mm were found using the lowest bandwidth of 122Hz per pixel. There was a dose difference of <0.5% between distorted and undistorted treatment plans. The 90% confidence intervals of the mean difference between the dCT and CT treatment plans were all within an equivalence interval of (-0.5, 0.5) for all investigated plan quality measures. Patient-induced susceptibility distortions at high field strengths in closed bore magnetic resonance scanners are larger than residual system distortions after using vendor-supplied 3-dimensional correction for the delineated regions studied. However, errors in dose due to disturbed patient outline and shifts caused by patient-induced susceptibility effects are below 0.5%.

Management of Severe Equinovalgus in Patients With Cerebral Palsy by Naviculectomy in Combination With Midfoot Arthrodesis.

Equinovalgus deformity is the second most common deformity in cerebral palsy and may be flexible or rigid. Several operative methods from joint sparing to arthrodesis have been described with varying success rates. The aim of this study was to investigate the effectiveness of naviculectomy in combination with midfoot arthrodesis (talo-cuneiform and calcaneocuboid arthrodesis) in the correction of a rigid equinovalgus foot deformity in cerebral palsy. Forty-eight rigid equinovalgus feet were operated upon in 30 patients from 2008 to 2013. Of these, 44 feet in 26 patients with cerebral palsy (Gross Motor Function Classification System III, IV, or V) with follow-up of more than 2 years were included in the study. The mean age at surgery was 18.1 years. The outcomes were measured objectively using radiographic angles and subjectively using 5 questions to be answered by the caregiver. The feet were then graded into excellent, good, fair, and poor. The mean follow-up was 5.0 ± 1.7 years. Excellent to good results were obtained in 81% of the feet. Both objective and subjective outcomes improved significantly postoperatively ( P < .001). Three feet in 2 patients were graded as poor and underwent a revision operation for pain and recurrence. Naviculectomy in combination with midfoot arthrodesis enabled a good 3-dimensional correction of the forefoot. However, the procedure did not necessarily correct the fixed subtalar joint deformity. Several additional bony and soft-tissue procedures were necessary to achieve a complete correction in these difficult feet. Level IV, retrospective case series.

Computer-assisted planning and patient-specific guides for the treatment of midshaft clavicle malunions

The surgical treatment of malunions after midshaft clavicle fractures is associated with a number of potential complications and the surgical procedure is challenging. However, with appropriate and meticulous preoperative surgical planning, the surgical correction yields satisfactory results. The purpose of this study was to provide a guideline and detailed overview for the computer-assisted planning and 3-dimensional (3D) correction of malunions of the clavicle. The 3D bone surface models of the pathologic and contralateral sides were created on the basis of computed tomography data. The computer-assisted assessment of the deformity, the preoperative plan, and the design of patient-specific guides enabling compression plating are described. We demonstrate the benefit and versatility of computer-assisted planning for corrective osteotomies of malunions of the midshaft clavicle. In combination with patient-specific guides and compression plating technique, the correction can be performed in a more standardized fashion. We describe the determination of the contact-optimized osteotomy plane. An osteotomy along this plane facilitates the correction and enlarges the contact between the fragments at once. We further developed a technique of a stepped osteotomy that is based on the calculation of the contact-optimized osteotomy plane. The stepped osteotomy enables the length to be restored without the need of structural bone graft. The application of the stepped osteotomy is presented for malunions of the clavicle with shortening and excessive callus formation. The 3D preoperative planning and patient-specific guides for corrective osteotomies of the clavicle may help reduce the number of potential complications and yield results that are more predictable.