Midterm Outcomes of Multimodal Approach to Treating Severe Scoliosis in Patients With Osteogenesis Imperfecta.

INTRODUCTION: The surgical management of severe scoliosis in patients with osteogenesis imperfecta (OI) is challenging because of curve rigidity, small stature, and inherent bone fragility. This study evaluated the midterm outcomes of our multimodal approach to address these issues, integrating perioperative bisphosphonate therapy, preoperative/intraoperative traction, various osteotomies, segmental pedicle screw instrumentation with cement augmentation, and bone morphogenetic protein-2 application. METHODS: A single-center retrospective review of 30 patients (average age 14.1 ± 2.2 years; 18 were female) diagnosed with OI and scoliosis was conducted. These patients underwent posterior spinal fusion between 2008 and 2020 and completed a minimum follow-up of 2 years. We measured radiographic parameters at each visit and reviewed the incidence of complications. A mixed-effects model was used to evaluate changes in radiographic parameters from preoperative measurements to the first and latest follow-ups. RESULTS: The patient cohort consisted of 2 individuals with type I OI, 20 with type III, 6 with type IV, and 2 with other types (types V and VIII). Surgical intervention led to a notable improvement in the major curve magnitude from 76° to 36°, with no notable correction loss. In addition, the minor curve, apical vertical translation, lowest instrumented vertebra tilt, and pelvic obliquity were also improved. In the sagittal plane, thoracic kyphosis and lumbar lordosis remained unchanged while thoracolumbar kyphosis markedly improved. Two patients experienced proximal junctional kyphosis with screw pullout, one of whom required revision surgery. One patient developed a superficial infection that was successfully treated with oral antibiotics. No instances of neurologic deficits or cement extravasation were observed. DISCUSSION: This study demonstrated the effectiveness and safety of our multimodal approach to treating scoliosis in patients with OI, achieving a 53% major curve correction with minimal complications over 2-year follow-up. These findings provide notable insights into managing scoliosis in this population. LEVEL OF EVIDENCE: Level IV (case series).

Multicenter Series of Deformity Correction Using Guided Growth in the Setting of Osteogenesis Imperfecta.

BACKGROUND: The mainstay of deformity correction and fracture prevention for patients with osteogenesis imperfecta (OI) includes osteotomies and intramedullary rodding. Guided growth, described in the setting of skeletal dysplasias, offers a less invasive means of deformity correction. We report a multicenter case series of guided growth procedures in the setting of OI. METHODS: We retrospectively reviewed patients with OI at three institutions from April 2012 to April 2019: 18 patients underwent guided growth for angular deformity correction with minimum 1-year follow-up or full deformity correction and removal of guided growth hardware. Clinical characteristics, deformity measurements, and complications were collected. Distal femoral and proximal tibial hemiepiphysiodesis was performed using figure-of-eight plates and screws, and distal tibial medial hemiepiphysiodesis with cannulated screws. Preoperative and postoperative lateral distal femoral angle, medial proximal tibial angle, and lateral distal tibial angle were measured. Frequency and descriptive statistics were completed. RESULTS: Eighteen patients with OI (five-I, four-III, six-IV, three-V) underwent 33 guided growth procedures with mean follow-up of 3.09 years; all received routine bisphosphonate treatment. Preoperative and postoperative mean joint angles were measured. The location for hemiepiphysiodesis included 8 distal femoral medial, 2 distal femoral lateral, 8 proximal tibial medial, 3 proximal tibial lateral, and 12 distal tibial medial. Twelve of the 33 procedures were in patients who had an intramedullary rod; 1 demonstrated backout of the epiphyseal and metaphyseal screws of a distal femoral medial figure-of-eight plate. It was revised to a larger plate with longer screws and removed upon completion of deformity correction. CONCLUSION: Guided growth may be used as an effective means of angular deformity correction with dysplastic OI bone. Having an intramedullary rod did not preclude the use of a guided growth technique. One procedure demonstrated screw backout. Given the short stature associated with OI, performing a guided growth procedure at an early enough age to allow time for correction should be considered. LEVEL OF EVIDENCE: Level IV-case series.

A novel risk calculator predicting surgical site infection after spinal surgery in patients with cerebral palsy.

AIM: To develop and validate a risk calculator based on preoperative factors to predict the probability of surgical site infection (SSI) in patients with cerebral palsy (CP) undergoing spinal surgery. METHOD: This was a multicenter retrospective cohort study of pediatric patients with CP who underwent spinal fusion. In the development stage, preoperative known factors were collected, and a risk calculator was developed by comparing multiple models and choosing the model with the highest discrimination and calibration abilities. This model was then tested with a separate population in the validation stage. RESULTS: Among the 255 patients in the development stage, risk of SSI was 11%. A final prediction model included non-ambulatory status (odds ratio [OR] 4.0), diaper dependence (OR 2.5), age younger than 12 years (OR 2.5), major coronal curve magnitude greater than 90° (OR 1.3), behavioral disorder/delay (OR 1.3), and revision surgery (OR 1.3) as risk factors. This model had a predictive ability of 73.4% for SSI, along with excellent calibration ability (p = 0.878). Among the 390 patients in the validation stage, risk of SSI was 8.2%. The discrimination of the model in the validation phase was 0.743 and calibration was p = 0.435, indicating 74.3% predictive ability and no difference between predicted and observed values. INTERPRETATION: This study provides a risk calculator to identify the risk of SSI after spine surgery for patients with CP. This will allow us to enhance decision-making and patient care while providing valid hospital comparisons, public reporting mechanisms, and reimbursement determinations.

Challenges with Fassier-Duval rod exchanges in congenital pseudarthrosis of the tibia: explant roadblock and solution.

Congenital pseudarthrosis of the tibia (CPT) is characterized by anterolateral tibial bowing and hamartomatous periosteum that predisposes it to fracture. Fassier-Duval telescopic rods can improve the structural integrity of bone segments after reconstruction. We present our experience treating CPT with the Fassier-Duval rod and a novel technique for Fassier-Duval exchange that was developed after extraction failed in one patient. Patients were identified who underwent treatment with Fassier-Duval rods for CPT between 2007 and 2016 and had undergone their first rod exchange. Medical records were reviewed, and complications were classified using the system of Cherkashin. Four patients had an average age at the initial insertion of 6 years 4 months (4-9 years). The average follow-up duration after initial Fassier-Duval implantation was 5.4 years (2.7-8.1 years). Seven Category 2 complications were associated with the Fassier-Duval rod: interlocking K-wire migration (2), lengthening failure (2), explant failure (1), distal migration of female rod through physis (1) and male rod portion proximally migrating through physis (1). Three patients underwent one rod exchange [average 3.2 years after implantation (range, 2.7-3.9 years)]. One patient underwent two rod exchanges (2.9 and 6.9 years after initial implantation). The second attempt at exchange failed; this failure prompted the development of custom trephines to remove the hard bone that can encase the distal male segment. The use of custom trephines was made necessary by dense sclerotic bone at the previous pseudarthrosis site. We recommend that custom trephines be available during Fassier-Duval rod extraction to avoid failed retrieval. Level of evidence: Level IV (Case series).

Congenital Pseudarthrosis of the Tibia Associated With Cleidocranial Dysostosis: Case Report and Literature Review.

CASE: We describe a case of 2 individually rare diseases existing comorbidly in the form of congenital pseudarthrosis of the tibia (CPT) coincident with cleidocranial dysostosis and provide a review of the literature, including the sole preexisting documented coincidence. CONCLUSION: Understanding, treatment, and surgical protocol of CPT have changed considerably since this comorbidity was last reported. Updates include synostosis, periosteal grafting, the use of bone morphogenetic protein, and bisphosphonates. Our case varies from the previous in associated disorder and family history. The relationship between CBFA1 and RUNX2 genes may hold the key, but further study is needed.

Cervical kyphosis: A predominant feature of patients with osteogenesis imperfecta type 5.

OBJECTIVES: Osteogenesis imperfecta (OI) is a heterogeneous group of genetic disorders of connective tissue that cause skeletal fragility and extra-skeletal manifestations. Classically, four different types of OI were distinguished. Type 5 OI was added due to its distinct clinical and radiographic features. In 2012, two independent groups identified a recurrent heterozygous c.-14C>T mutation in IFITM5 as the responsible genetic change for this type of OI. To our knowledge, cervical kyphosis has not been identified in the literature as a finding in type 5 OI patients. This is a retrospective review of a cohort of patients with type 5 OI and a description of associated cervical spine deformity. METHODS: After institutional review board approval, a retrospective review identified 13 patients with type 5 OI. Clinical, radiologic, and genetic data from 2002 to 2020 were reviewed. RESULTS: We identified 13 patients with clinical diagnosis of type 5 OI. Twelve had molecular confirmation and the classic IFITM5, c.14C>T gene mutation was identified. The remaining individual did not undergo genetic testing. Dentinogenesis imperfecta was observed in one patient, while blue sclerae or hearing loss were not present. All patients had at least one fracture and four underwent intramedullary rodding. Radiologic features included subphyseal metaphyseal radiodense line in 12/13 patients (92%), interosseous membrane calcification in seven of 13 patients (54%) (more commonly noted in the upper extremities), and hypertrophic callus in six of 13 patients (46%). Thoracolumbar spinal deformities were seen in six of 13 patients (46%) with two of these individuals requiring surgery. Cervical kyphosis was noted in nine of 13 individuals (69%) ranging in age from 3 months to 22 years. Anterior wedging of the cervical vertebral bodies was noted in the absence of any fractures. Six of nine individuals demonstrated listhesis of C2-C3 or C3-C4 segment. Magnetic resonance imaging studies were performed and reviewed in patients with cervical kyphosis and subluxation; three patients showed narrowing of spinal canal without cervical cord compression and one asymptomatic patient showed impingement of the spinal cord. CONCLUSIONS: Cervical kyphosis appears to be a common feature of type 5 OI. It can be a presenting and apparently life-long association and does not appear to be caused by vertebral body fractures. Evaluation for cervical kyphosis should be performed in patients with a suspected or confirmed diagnosis of type 5 OI. Furthermore, if cervical kyphosis is noted in an individual with OI, type 5 OI should be considered.Level of evidence: IV.

Evaluation of Fracture and Osteotomy Union in the Setting of Osteogenesis Imperfecta: Reliability of the Modified Radiographic Union Score for Tibial Fractures (RUST).

BACKGROUND: Evaluation of the union of osteotomies and fractures in patients with osteogenesis imperfecta (OI) is a critical component of patient care. Studies of the OI patient population have so far used varied criteria to evaluate bony union. The radiographic union score for tibial fractures (RUST), which was subsequently revised to the modified RUST, is an objective standardized method of evaluating fracture healing. We sought to evaluate the reliability of the modified RUST in the setting of the tibias of patients with OI. METHODS: Tibial radiographs of 30 patients with OI fractures, or osteotomies were scored by 3 observers on 2 separate occasions. Each of the 4 cortices was given a score (1=no callus, 2=callus present, 3=bridging callus, and 4=remodeled, fracture not visible) and the modified RUST is the sum of these scores (range, 4 to 16). The interobserver and intraobserver reliabilities were evaluated using intraclass coefficients (ICC) with 95% confidence intervals. RESULTS: The ICC representing the interobserver reliability for the first iteration of scores was 0.926 (0.864 to 0.962) and for the second series was 0.915 (0.845 to 0.957). The ICCs representing the intraobserver reliability for each of the 3 reviewers for the measurements in series 1 and 2 were 0.860 (0.707 to 0.934), 0.994 (0.986 to 0.997), and 0.974 (0.946 to 0.988). CONCLUSIONS: The modified RUST has excellent interobserver and intraobserver reliability in the setting of OI despite challenges related to the poor quality of the bone and its dysplastic nature. The application and routine use of the modified RUST in the OI population will help standardize our evaluation of osteotomy and fracture healing. LEVEL OF EVIDENCE: Level III-retrospective study of nonconsecutive patients.

Osteogenesis Imperfecta: A Pediatric Orthopedic Perspective.

Osteogenesis imperfecta is a genetically and phenotypically heterogeneous disorder related to a defect or deficiency in the production of type I collagen. It is characterized by brittle bones, fractures, spine and extremity deformity, and a host of extraskeletal manifestations. Type I collagen is present in bone, tendons, ligaments, skin, dentin, and the sclera of the eye and other connective tissues. Osteogenesis imperfecta includes a multitude of disease manifestations that may be present at birth or develop over time and vary depending on the severity of the disease. This article describes the disease presentation and management considerations from a pediatric orthopedic perspective.

Bone Ninja Mobile App for Reverse Planning Method in Internal Limb Deformity and Lengthening Surgery.

AIM: To report whether Bone Ninja (BN) is a reliable tool to teach the reverse planning method (RPM) for implantable intramedullary (IM) limb-lengthening devices and for deformity correction surgery. BACKGROUND: Motorised fully implantable implantable intramedullary (IM) lengthening devices have been gaining popularity all over the world for limb-lengthening procedures. Multiple advantages have been demonstrated over external fixator-controlled lengthening. Mechanical axis deviation may result if careful preoperative planning and surgical intervention are not completed for femur cases. The RPM proposed by Baumgart has been shown to be an accurate means of arriving at the desired end point. The RPM addresses the ideal correction position accounting for length, angulation, and translation created during lengthening along the nail axis. The original description calls for the use of life-size paper tracings of the bone and large light boxes to allow planning. We propose an alternative method using a digital tool that is readily available. The BN mobile app was developed for patient/physician education and is available for the Apple iPad platform. Bone Ninja has been shown to have similar accuracy for measurements of the limb length and deformity angles when compared to the gold standard picture archiving and communication systems (PACSs). TECHNIQUE: We used BN (version 4.2) on an iPad mini to perform the same RPM steps, using the same terminology originally described by Baumgart. CONCLUSION: Bone Ninja is a simple validated deformity correction tool with accuracy comparable to PACS. It is a reasonable alternative to paper/pencil cutouts for applying RPM for IM limb lengthening and deformity correction surgery. CLINICAL SIGNIFICANCE: We proposed a digitised RPM for internal limb-lengthening surgeries, which is highly feasible and practical to use conveniently without the need for the traditional tedious paper-cutting procedure and related equipment. HOW TO CITE THIS ARTICLE: Hung AL-H, McClure PK, Franzone JM, et al. Bone Ninja Mobile App for Reverse Planning Method in Internal Limb Deformity and Lengthening Surgery. Strategies Trauma Limb Reconstr 2019;14(2):72-76.

Categorization of the Usage of Adjunctive Structural Allograft Bone Graft in Extremity Surgery for Patients with Osteogenesis Imperfecta.

Structural allograft bone plays a role in orthopedic surgery. Our purpose is to describe the methods of using structural allograft in extremity reconstruction surgery in patients with osteogenesis imperfecta (OI) and create a classification of usage with a single-center review of OI extremity cases from January 2002 to February 2017. Structural allograft was used in 19 bone segments in 15 patients with type III OI. Four categories of usage were defined: (1) interpositional, (2) onlay, (3) inlay, and (4) blocking to prevent rod migration. The mean time to incorporation was 5.4 months (range 1-16). Structural allograft bone incorporates into OI bone and may be a supplement to intramedullary fixation.

Reuse of Single-Use HemaClear Exsanguination Tourniquets: A Technique Note.

Surgical tourniquets have an important role in limiting blood loss and improving surgical visualization. The HemaClear® tourniquet is a sterile silicone-ring tourniquet designed to exsanguinate as it is applied. HemaClear tourniquets may be rolled all the way up to the groin or the axilla and thus provide a larger operating field than standard wide pneumatic tourniquets. Although designed for single use, we propose here a technique permitting the reapplication of a HemaClear tourniquet on the contralateral limb in the setting of bilateral-extremity sequential surgical procedures. Such one time reuse decreases health-care costs.

Is there an association between chronicity of patellar instability and patellofemoral cartilage lesions? An arthroscopic assessment of chondral injury.

The purpose of this study was to investigate the association between chronicity of patellar instability on the prevalence, grade, and location of chondral lesions in patients with recurrent patellar instability. Patellofemoral chondral status was documented and graded according to the Outerbridge classification in 38 patients who underwent arthroscopic examination at the time of a medial patellofemoral ligament reconstruction procedure. Chondral lesions of any location were observed in 63.2% of patients. Patellar and trochlear lesions were observed in 57.9 and 13.2% of patients, respectively. There was a significantly higher duration of patellar instability in patients with a trochlear lesion versus those without a trochlear lesion (p < 0.01), and in patients with combined patellar and trochlear lesions versus those without both patellar and trochlear lesions (p < 0.01). There was a significant correlation between chronicity of patellar instability and Outerbridge grade of trochlear chondral injury (p = 0.01). Chi-squared analysis revealed that chronicity of patellar instability greater than 5 years was significantly associated with the likelihood of trochlear lesions (p < 0.05). We conclude that patients with increasing chronicity of patellar instability may have a higher likelihood of and higher grade of patellofemoral chondral injuries, specifically for trochlear lesions.

The role of posterior spinal osteotomies in pediatric spinal deformity surgery: indications and operative technique.

The primary goals of spinal deformity surgery are to prevent the progression of further deformity and to improve sagittal and coronal balance. Although increasingly powerful instrumentation has greatly facilitated these treatment goals, osteotomy of the spine is sometimes necessary to address more significant deformity. This review provides a detailed overview of posterior spinal osteotomies, which have gained increased attention as an adjunct to the treatment of complex pediatric spine deformity. The indications, operative technique, and advantages and disadvantages of the Smith-Petersen, pedicle subtraction and vertebral column resection osteotomies will be discussed, as well as operative considerations generally applicable to spinal deformity surgery involving correction with osteotomies.

The Ca2+/calmodulin-dependent protein kinase kinases are AMP-activated protein kinase kinases.

The AMP-activated protein kinase (AMPK) is an important regulator of cellular metabolism in response to metabolic stress and to other regulatory signals. AMPK activity is absolutely dependent upon phosphorylation of AMPKalphaThr-172 in its activation loop by one or more AMPK kinases (AMPKKs). The tumor suppressor kinase, LKB1, is a major AMPKK present in a variety of tissues and cells, but several lines of evidence point to the existence of other AMPKKs. We have employed three cell lines deficient in LKB1 to study AMPK regulation and phosphorylation, HeLa, A549, and murine embryo fibroblasts derived from LKB(-/-) mice. In HeLa and A549 cells, mannitol, 2-deoxyglucose, and ionomycin, but not 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAR), treatment activates AMPK by alphaThr-172 phosphorylation. These responses, as well as the downstream effects of AMPK on the phosphorylation of acetyl-CoA carboxylase, are largely inhibited by the Ca(2+)/ calmodulin-dependent protein kinase kinase (CaMKK) inhibitor, STO-609. AMPKK activity in HeLa cell lysates measured in vitro is totally inhibited by STO-609 with an IC50 comparable with that of the known CaMKK isoforms, CaMKKalpha and CaMKKbeta. Furthermore, 2-deoxyglucose- and ionomycin-stimulated AMPK activity, alphaThr-172 phosphorylation, and acetyl-CoA carboxylase phosphorylation are substantially reduced in HeLa cells transfected with small interfering RNAs specific for CaMKKalpha and CaMKKbeta. Lastly, the activation of AMPK in response to ionomycin and 2-deoxyglucose is not impaired in LKB1(-/-) murine embryo fibroblasts. These data indicate that the CaMKKs function in intact cells as AMPKKs, predicting wider roles for these kinases in regulating AMPK activity in vivo.