Limb Lengthening With Precice Intramedullary Lengthening Nails in Children and Adolescents.

BACKGROUND: The Precice intramedullary bone lengthening nail has been used in our department since 2013. We sought to determine the efficacy and safety of intramedullary limb lengthening with Precice nails in children and adolescents. METHODS: We retrospectively investigated patients 18 years and younger who underwent lower-limb lengthening using the Precice nail. Radiologic and clinical outcome data were obtained from a prospective database. The minimum postimplantation follow-up was 12 months. Between March 2013 and March 2020, 161 patients underwent limb lengthening with a Precice nail; 76 patients met the inclusion criteria. RESULTS: We used 84 nails in 76 patients (68 femurs and 16 tibias). Femoral nails were inserted using an antegrade approach in 57 patients and a retrograde approach in 11. The mean age at surgery was 16 years (range, 9 to 18 y). The mean lengthening was 33 mm (range, 14 to 80 mm) with additional acute axial or rotational malalignment correction in 16 segments. At the last follow-up (mean=2.1, years; range, 1 to 5 y), all regenerates had healed and all patients were mobile with full weight-bearing. Complications that necessitated surgical revision occurred in 6 patients (8%), and the desired lengthening was not achieved in 2 patients. Postlengthening malalignment occurred in 4 patients (5 tibial nails). The weight-bearing index, defined as days from surgery to full weight-bearing/cm of lengthening, was a mean of 45 days (range, 7 to 127 d/cm). CONCLUSIONS: The Precice nail facilitated reliable and safe bone lengthening and was associated with a low complication rate. Correction of additional malalignment was possible by applying intraoperative acute correction or guided growth. LEVEL OF EVIDENCE: Level IV-therapeutic study investigating the results of treatment.

Correction of post-traumatic lower-limb discrepancy with Precice intramedullary lengthening nails: a review of 34 adults with an average follow-up of 2 years.

BACKGROUND AND PURPOSE: We report results and complications of gradual bone lengthening for post-traumatic lower-limb length discrepancy (LLD) with Precice intramedullary lengthening nails in 34 adults. PATIENTS AND METHODS: Inclusion criteria were lower-limb lengthening using the Precice nail, posttraumatic etiology, age older than 18 years, and minimum follow-up of 12 months after implantation. 34 patients met the inclusion criteria. Radiological and clinical outcome data were collected. RESULTS: Precice lengthening was performed in the femur in 28 patients (21 antegrade, 7 retrograde) and in the tibia in 6. Mean patient age at time of surgery was 32 years (18-72). Mean preoperative LLD was 31 mm (20-71). Acute correction of axial or rotational malalignment was performed in 11 segments. At final follow-up (mean 2 years [1.1-3.6]), 33 of 34 nails had been removed. All lengthening sites were healed, and all patients mobilized with full weight-bearing. 14 adverse events occurred in 11 patients and were categorized as problems (n = 5), obstacles (n = 3), and complications (n = 6). Unplanned surgery was necessary in 7 patients, 3 of whom did not complete treatment with Precice. INTERPRETATION: Correction of posttraumatic LLD with or without axial malalignment using Precice intramedullary lengthening nails is associated with a low number of complications and good functional outcome. However, one-fifth of patients in this series needed further unplanned surgery for revision of obstacles or complications.

Leg lengthening and deformity correction in rare bone diseases: a multidisciplinary approach.

Congenital and acquired conditions presenting with leg length discrepancy, leg deformity or short stature are not only a challenge for paediatric orthopaedic surgeons in terms of treatment options but may also involve a number of medical specialties due to the complex clinical manifestations of the diseases. Various surgical treatment options are available for these rare genetic diseases, including bone lengthening and growth inhibition techniques for lower limb discrepancy, as well as guided growth and other surgical procedures for correction of angular deformities. Surgical techniques may be similar, but the treatment plans and specific multidisciplinary approaches may differ. The present report is focused on paediatric orthopaedic and multidisciplinary aspects of the treatment of rare bone diseases. We address the clinical presentation of these diseases, gait and surgical procedures for conditions such as achondroplasia, X­linked hypophosphatemia and osteogenesis imperfecta. We also provide a short overview of other rare bone diseases.

Is the Apert foot an overlooked aspect of this rare genetic disease? Clinical findings and treatment options for foot deformities in Apert syndrome.

BACKGROUND: Apert syndrome is characterised by the presence of craniosynostosis, midface retrusion and syndactyly of hands and feet, thus, synonymously referred to as acrocephalosyndactyly type I. Considering these multidisciplinary issues, frequently requiring surgical interventions at an early age, deformities of the feet have often been neglected and seem to be underestimated in the management of Apert syndrome. Typical Apert foot features range from complete fusion of the toes and a central nail mass to syndactyly of the second to fifth toe with a medially deviated great toe; however, no clear treatment algorithms were presented so far. This article reviews the current existing literature regarding the treatment approach of foot deformities in Apert syndrome. STATE-OF-THE-ART TOPIC REVIEW: Overall, the main focus in the literature seems to be on the surgical approach to syndactyly separation of the toes and the management of the great toe deformity (hallux varus). Although the functional benefit of syndactyly separation in the foot has yet to be determined, some authors perform syndactyly separation usually in a staged procedure. Realignment of the great toe and first ray can be performed by multiple means including but not limited to second ray deletion, resection of the proximal phalanx delta bone on one side, corrective open wedge osteotomy, osteotomy of the osseous fusion between metatarsals I and II, and metatarsal I lengthening using gradual osteodistraction. Tarsal fusions and other anatomical variants may be present and have to be corrected on an individual basis. Shoe fitting problems are frequently mentioned as indication for surgery while insole support may be helpful to alleviate abnormal plantar pressures. CONCLUSION: There is a particular need for multicenter studies to better elaborate surgical indications and treatment plans for this rare entity. Plantar pressure measurements using pedobarography should be enforced in order to document the biomechanical foot development and abnormalities during growth, and to help with indication setting. Treatment options may include conservative means (i.e. insoles, orthopedic shoes) or surgery to improve biomechanics and normalize plantar pressures. LEVEL OF EVIDENCE: Level V.

Outcomes after thumb carpometacarpal joint stabilization with an abductor pollicis longus tendon strip for the treatment of chronic instability.

INTRODUCTION: Instabilities of the thumb carpometacarpal (CMC) joint, caused by idiopathic ligamentous hyperlaxity, trauma or other conditions may lead to pain, functional impairment and eventually osteoarthritis. Several techniques have been described to enhance stability of the CMC 1. The aim of this study was to evaluate postoperative outcomes after CMC 1 joint stabilization using a soft-tissue procedure in patients with chronic instability. MATERIALS AND METHODS: This study was designed as a retrospective study with a single follow-up visit after a minimum of 1 year postoperatively. All patients who underwent stabilization of the CMC 1 with an abductor pollicis longus (APL) tendon strip for chronic, habitual instability were re-assessed using clinical examination, dedicated outcome scores [Visual Analogue Scale (VAS); The Disability of the Arm, Shoulder and Hand (DASH) score; Nelson score; Kapandji opposition score], grip and pinch strength measurements, and radiographic examination. RESULTS: 12 patients (15 operated thumbs) with a mean age at surgery of 23.2 (± 9.3) years were included after a mean follow-up period of 3.5 (± 1.3) years. The postoperative outcomes indicated excellent results, with a mean DASH score of 13.3 (± 11.3), VAS 1.1 at rest (and 2.8 during stress) and Nelson score of 87.7 (± 11.3). Postoperative grip, pinch strength and passive stability were not significantly different between operated and non-operated sides (p = 0.852; p = 0.923 and p = 0.428, respectively). We observed one case of recurrent instability besides no other complications. However, patients with trapezium hypoplasia (5 of 12) were more prone to signs of radiographic instability during stress testing. CONCLUSIONS: Thumb carpometacarpal stabilization with an APL tendon strip yielded excellent clinical outcomes and low morbidity in the mid-term. However, long-term follow-up is needed to assess specifically whether patients with trapezium hypoplasia may be more prone to clinical symptom recurrence than those with normal anatomy. LEVEL OF EVIDENCE: Level IV.

The Subtemporal Approach to the Lateral Midbrain with and without Zygomatic Osteotomy: An Anatomical Study.

The subtemporal approach provides a narrow operative corridor to the crus cerebrum and adjacent structures of the crural, interpeduncular, and ambient cistern. Addition of a zygomatic osteotomy widens this narrow corridor and spares retraction of the temporal lobe. We investigate and compare the morphometric parameters of the subtemporal approach with versus without zygomatic osteotomy. On each side of four cadaveric heads, a temporal craniotomy was performed to gain access to the crus cerebrum and adjacent subarachnoid cisterns using a subtemporal approach. Operative corridor width and corridor working angle were measured with and without brain retraction on each specimen side. Next, a zygomatic osteotomy was performed followed by full downward reflection of the temporalis muscle and further drilling of the squamous part of the temporal bone. Lastly, operative corridor width and corridor working angle were measured again for comparison. The subtemporal operating corridor was (mean/SD): 5.8/2.6 mm without retraction, 11.4/4.3 mm with retraction, and 13.5/6.5° working angle. After addition of a zygomatic osteotomy, the operative corridor was 8/9.2/4.3 mm without retraction, 14.7/4.5 mm with retraction, 31.8/3.1° working angle. Zygomatic osteotomy significantly increased the operative corridor working angle of the subtemporal approach. Furthermore, we demonstrate a direct approach into the interpeduncular fossa. Clin. Anat. 32:710-714, 2019. © 2019 Wiley Periodicals, Inc.

Achondroplasia current concept of orthopaedic management.

Achondroplasia, the most common form of inherited disproportionate short stature, is caused by mutations in the fibroblast growth factor receptor 3 gene. The typical clinical features of achondroplasia include short stature, rhizomelic disproportion, joint hyperlaxity, spinal deformity and deformity of the upper and lower limbs. The latter are among the challenges of state-of-the-art orthopaedic treatment plans and significantly contribute to the burden of the disease in individuals with achondroplasia. Multidisciplinary preoperative individual decision-making concerning surgical interventions should be considered. New medical treatments for achondroplasia have been developed and (some) have been approved for clinical use in several countries. While the number of research articles on achondroplasia is increasing rapidly, many unknown or controversial orthopaedic topics remain. Furthermore, in view of new medical developments with improvements in growth and potentially other effects, the timing and algorithms of orthopaedic treatments (e.g. guided growth, limb lengthening and deformity correction) need to be re-evaluated. While standing height is the primary research focus in medical therapy, it is crucial to comprehensively assess orthopaedic parameters in this multifactorial disease. The current treatment of patients with achondroplasia requires specialised multidisciplinary centres with transitional care and individual orthopaedic counselling.

Lower limb maltorsion and acetabular deformity in children and adolescents with X-linked hypophosphatemia.

Background: X-linked hypophosphatemia (XLH) is a rare monogenetic skeletal disorder. Lower limb deformities contribute substantially to impaired gait quality and burden of disease in patients with XLH. Standardized data regarding onset and severity of lower limb maltorsion are unavailable. This study aimed to evaluate lower limb maltorsion using rotational magnetic resonance imaging (MRI) and computed tomography (CT). Methods: Rotational MRI and CT of children and adolescents with verified XLH were evaluated retrospectively. Femoral and tibial torsion, acetabular anteversion, and axial acetabular coverage were measured and compared with published age-adapted radiographic, clinical measurements and MRI data, respectively. Results: Fifteen patients (mean age, 10.7 years) were included in the study. Decreased femoral torsion was observed in 47% (14/30 femora) and femoral retrotorsion in 17% (5/30 femora). Ten of 13 hips with coxa vara deformity presented with decreased femoral antetorsion. Reduced external tibial torsion manifested in 64% (18/28 tibiae). Abnormal axial femoral head coverage was present in 67% (20/30 hips), whereas 53% (16/30 hips) showed increased acetabular anteversion. Conclusion: Femoral and tibial torsional pathologies were found in children and adolescents with XLH. The occurrence of severe femoral retrotorsion in a 2-year-old child prior to ambulation raises questions regarding the biomechanical impact of gait on the development of torsional deformities in XLH.

Clinical, Radiographic, and Biomechanical Evaluation of the Upper Extremity in Patients with Osteogenesis Imperfecta.

Introduction: Osteogenesis imperfecta (OI) is a hereditary disorder primarily caused by mutations in type I collagen genes, resulting in bone fragility, deformities, and functional limitations. Studies on upper extremity deformities and associated functional impairments in OI are limited. This cross-sectional study aimed to evaluate upper extremity deformities and functional outcomes in OI. Methods: We included patients regardless of their OI subtypes with a minimum age of 7 years. Radiographic analysis of radial head dislocation, ossification of the interosseous membrane, and/or radioulnar synostosis of the forearm were performed, and deformity was categorized as mild, moderate, or severe. Clinical evaluation was performed using the Quick Disabilities of Arm, Shoulder, and Hand (qDASH) questionnaire and shoulder-elbow-wrist range of motion (ROM). Three-dimensional motion analysis of the upper limb was conducted using the Southampton Hand Assessment Procedure (SHAP). The SHAP quantifies execution time through the Linear Index of Function (LIF) and assesses the underlying joint kinematics using the Arm Profile Score (APS). Additionally, the maximum active Range of Motion (aRoM) was measured. Results: Fourteen patients aged 8 to 73 were included. Radiographic findings revealed diverse deformities, including radial head dislocation, interosseous membrane ossification, and radioulnar synostosis. Six patients had mild, six moderate, and two severe deformities of the upper extremity. Severe deformities and radial head dislocation correlated with compromised ROM and worse qDASH scores. The qDASH score ranged from 0 to 37.5 (mean 11.7). APS was increased, and LIF was reduced in OI-affected persons compared with non-affected peers. APS and LIF also varied depending on the severity of bony deformities. aRoM was remarkably reduced for pro-supination. Conclusion: Patients with OI showed variable functional impairment from almost none to severe during daily life activities, mainly depending on the magnitude of deformity in the upper extremity. Larger multicenter studies are needed to confirm the results of this heterogeneous cohort. Level of evidence: Retrospective clinical study; Level IV.

An Experimental Model for Fluid Dynamics and Pressures During Endoscopic Lumbar Discectomy.

OBJECTIVE: Endoscopic spine surgery is an emerging technique of minimally invasive spine surgery. However, headache, seizure, and autonomic dysreflexia are possible irrigation-related complications following full-endoscopic lumbar discectomy (FELD). Pressure elevation through fluid irrigation may contribute to these adverse events. A validated experimental model to investigate parameters for guideline definition is lacking. This study aimed to create an experimental setting for FELD with pressure assessments to prove the concept of repeatable and sensitive measurement of intracranial, intra- and epidural pressures during spine endoscopy. METHODS: To measure intradural pressure, catheters were introduced through a sacral approach and advanced to lumbar, thoracic, and cervical levels in human cadavers. Similarly, lumbar epidural and intracranial probes were placed. The dural sac was filled with Ringer solution to a physiologic pressure of 15 cmH2O. Lumbar endoscopy was performed on 3 human cadavers at the L3-4 level. Pressure changes were measured continuously at all sites and the effects of backflow-occlusion were monitored. RESULTS: Reproducibility of the experimental model was validated with catheters at the correct locations and stable compartmental pressure baselines at all levels for 3 specimens (mean±standard deviation: 1.3±2.9 mmHg, 9.0±2.0 mmHg, 6.0±1.2 mmHg, respectively). Pressure increase could be detected sensitively by closing the system with backflow-occlusion. CONCLUSION: An experimental setup for feasible, repeatable, and precise pressure measurement during FELD in a human cadaveric setup has been developed. This allows investigation of the effects of endoscopic techniques and pump pressures on intra-, epidural and intracranial pressure and enables ranges of safe pump pressures per clinical situations.

The ankle in XLH: Reduced motion, power and quality of life.

Background: X-linked hypophosphatemia (OMIM 307800) is a rare bone disease caused by a phosphate-wasting condition with lifelong clinical consequences. Those affected suffer from bone pain, complex skeletal deformities, impaired mobility and a reduced quality of life. Early osteoarthritis and reduced range of motion of the lower limbs are known pathologies in XLH patients. However, XLH-specific data on the affected compartments such as the ankle joint through the evaluation of radiographic and gait analysis data is still lacking. Patients and methods: In this cross-sectional study, patients with genetically verified XLH, age ≥ 16 - 50 years and a complete record of gait analysis and or radiographic analysis data were included. Clinical examination, radiological and gait analysis data were compared to norms using the dataset of our gait laboratory registry. Radiographic analysis included tibial deformity analysis and assessment of osteoarthritis and enthesopathies. Western Ontario and McMaster Universities Arthritis Index (WOMAC), SF36v2, American Orthopedic Foot and Ankle Society score (AOFAS) and the Foot and Ankle Outcome Score (FAOS) were used. Twentythree participants with 46 limbs were eligible for the study. Results: A total of 23 patients (n=46 feet) met the inclusion criteria. Patients with XLH had significantly reduced gait quality, ankle power and plantar flexion (p < 0.001) compared to a historic gait laboratory control group. Ankle valgus deformity was detected in 22 % and ankle varus deformity in 30 % of the patients. The subtalar joint (59.1%) as well as the anterior tibiotalar joint (31.1%) were the main localizations of moderate to severe joint space narrowing. Ankle power was decreased in moderate and severe subtalar joint space narrowing (p < 0.05) compared to normal subtalar joint space narrowing. No lateral or medial ligament instability of the ankle joint was found in clinical examination. Tibial procurvatum deformity led to lower ankle power (p < 0.05). Conclusions: This study showed structural and functional changes of the ankle in patients with XLH. Subtalar ankle osteoarthritis, patient reported outcome scores and clinical ankle restriction resulted in lower gait quality and ankle power.

[Osteogenesis imperfecta : A multidisciplinary challenge]. / Osteogenesis imperfecta : Eine multidisziplinäre Herausforderung.

Osteogenesis imperfecta (OI) describes a group of rare diseases which are associated with an increased tendency to bone fractures. In addition to the main symptom of fractures, OI is characterized by a variety of pediatric, pediatric orthopedic and anesthesiological challenges. The multidisciplinary expertise is mostly concentrated at specialized centers. The current treatment concepts aim at minimizing the fracture rate, prevention and treatment of deformities, pain reduction and improved mobility. In addition to pharmacotherapy, conservative and surgical measures are also applied. Scheduled interventions on the extremities are one of the most commonly performed operations in children with OI. Various intramedullary nailing techniques are available. This article addresses the important aspects of multidisciplinary care of children with OI concerning the treatment of the lower extremities.

Persistent Lower Limb Deformities Despite Amelioration of Rickets in X-Linked Hypophosphatemia (XLH) - A Prospective Observational Study.

Background: Gait deviations, lower limb pain and joint stiffness represent key symptoms in patients with X-linked hypophosphatemia (XLH, OMIM 307800), a rare disorder of mineral homeostasis. While the pathomechanism for rickets is well understood, the direct role of PHEX (Phosphate-regulating neutral endopeptidase) deficiency in non-rachitic features including complex deformities, skull and dental affections remains unclear. FGF23-inhibiting antibody treatment can normalize serum phosphate levels and to improve rickets in XLH patients. However, linear growth remains impaired and effects on lower limb deformity and gait are insufficiently studied. Aims: To characterize and evaluate the course of lower limb deformity in a case series of pediatric XLH patients receiving Burosumab therapy. Methods: Comparative assessment of planar radiographs, gait analysis, biochemical and clinical features of pediatric patients before and ≥12 months after initiation of FGF23-inhibiting was performed prospectively. Lower limb maltorsion was quantified by torsional MRI and gait analysis. Standardized deformity analysis of lower limb anteroposterior radiographs was conducted. Results: Seven patients (age 9.0 +/-3.6 years) were eligible for this study. All patients received conventional treatment before onset of antibody treatment. Maltorsion of the femur was observed in 8/14 legs using torsional MRI (mean antetorsion 8.79°). Maltorsion of the tibia was observed in 9/14 legs (mean external torsion 2.8°). Gait analysis confirmed MRI findings with femoral external malrotation prior to and one year after onset of Burosumab therapy. Internal foot progression (intoeing gait) remained pathological in all cases (mean 2.2°). Knee rotation was pathologically internal 10/14 legs. Mean mechanical axis deviation (MAD) of 16.1mm prior to Burosumab changed in average by 3.9mm. Three children underwent guided growth procedures within the observation period. Mild postprocedural rebound of frontal axis deviation was observed under Burosumab treatment in one patient. Conclusions: This is the first study to investigate lower limb deformity parameters quantitatively in children with XLH receiving Burosumab. One year of Burosumab therapy was associated with persistent maltorsion and frontal axis deviation (varus/valgus) despite improved rickets in this small, prospective uncontrolled study.

Lower Limb Deformity and Gait Deviations Among Adolescents and Adults With X-Linked Hypophosphatemia.

Background: X-linked hypophosphatemia (XLH) is a rare genetic disorder characterized by lower limb deformity, gait and joint problems, and pain. Hence, quality of life is substantially impaired. This study aimed to assess lower limb deformity, specific radiographic changes, and gait deviations among adolescents and adults with XLH. Design: Data on laboratory examination and gait analysis results were analyzed retrospectively. Deformities, osteoarthritis, pseudofractures, and enthesopathies on lower limb radiographs were investigated. Gait analysis findings were compared between the XLH group and the control group comprising healthy adults. Patients and Controls: Radiographic outcomes were assessed retrospectively in 43 patients with XLH (28 female, 15 male). Gait analysis data was available in 29 patients with confirmed XLH and compared to a healthy reference cohort (n=76). Results: Patients with XLH had a lower gait quality compared to healthy controls (Gait deviation index GDI 65.9% +/- 16.2). About 48.3% of the study population presented with a greater lateral trunk lean, commonly referred to as waddling gait. A higher BMI and mechanical axis deviation of the lower limbs were associated with lower gait scores and greater lateral trunk lean. Patients with radiologic signs of enthesopathies had a lower GDI. Conclusions: This study showed for the first time that lower limb deformity, BMI, and typical features of XLH such as enthesopathies negatively affected gait quality among adolescents and adults with XLH.

The prevalence of Vickers' ligament in Madelung's deformity: a retrospective multicentre study of 75 surgical cases.

In a retrospective multicentre study, we aimed to correlate clinical factors and findings on plain radiographs and MRI with the intraoperative presence of Vickers' ligament in Madelung's deformity. We screened the records, in which the absence or presence of Vickers' ligament was affirmatively indicated, of 75 consecutive operated extremities in 58 patients. In 83% a Vickers' ligament was observed intraoperatively. The whole bone Madelung type (as opposed to the distal type) and a distal radial notch were independent, significant predictors for the presence of the ligament. The correct Vickers detection rate using MRI was 85% of the 27 cases for which MRI was available. Thus, the MRI was a good but not perfectly reliable modality. We conclude that Vickers' ligament is present in the majority but not all cases with Madelung deformity. We advise that patients with a more severe type of Madelung's deformity and a distal radial notch should be monitored closely.Level of evidence: IV.

Disease-specific gait deviations in pediatric patients with X-linked hypophosphatemia.

BACKGROUND: X-linked hypophosphatemia (XLH) represents the most common genetic form of rickets featuring profound hypophosphatemia with associated skeletal and non-skeletal manifestations. Early onset gait disturbances contribute strongly to the burden of disease. However, no study has comprehensively characterized naturally occurring gait deviations in pediatric patients with XLH. RESEARCH QUESTIONS: Can disease-specific gait deviations and potentially influencing factors be identified by gait analysis in non-surgically treated children with XLH? METHODS: Gait laboratory assessments of 12 pediatric patients with XLH without previous long bone surgery was retrospectively analyzed and compared to age-matched healthy controls. Radiologic and clinical parameters of XLH patients were correlated with kinematic gait variables and gait scores. RESULTS: Reduced external knee rotation and increased external hip orientation was ubiquitous in children with XLH. Increased lateral trunk lean, or "waddling gait", occurred in five children and was associated with varus knee deformities. Overall, children with XLH showed a reduced Gait Deviation Index (GDI) compared to controls. Radiologic and gait analysis revealed complex combined frontal and torsional deformity of the lower limbs as a common feature in XLH. Higher Body Mass Index (BMI) was associated with both lateral trunk lean and impaired GDI. SIGNIFICANCE: Gait analysis is feasible to quantify gait deviations and lower limb deformities in pediatric patients with XLH. Specific gait characteristics including internal knee rotation and external hip rotation are common among patients with XLH and contribute to impaired gait scores. Our data suggest the use of gait and deformity data assessment as outcome parameters in future observational and interventional studies. Standardized assessment might contribute to targeted treatments to improve life quality in XLH patients.

Outcomes of patients with single-bone-forearm surgery: a clinical assessment and three-dimensional motion analysis.

The creation of a single-bone-forearm is a salvage procedure to stabilize the forearm. The purpose of this study was to investigate clinical outcomes and how these patients compensate for the lack of forearm rotation. We evaluated four patients (three children, one adult) who had undergone single-bone-forearm surgery. Patients were examined clinically and with three-dimensional motion analysis. We found these patients are generally capable to perform important activities of daily living (e.g. glass jug pouring), which would normally need forearm rotation. Motion analysis revealed remarkable compensatory motion at other joints during these activities. We conclude that patients with a single-bone-forearm can maintain a certain level of daily activities by using compensatory motions at other joints, although the time needed to complete the tasks may be longer. Level of evidence: IV.

Splitting of the semispinalis capitis muscle as a less invasive approach for atlantoaxial fusion - A technical note.

PURPOSE: Atlantoxial fusion with screw rod constructs traditionally requires subperiostal dissection of the C1/C2 muscle attachments, which may lead to postoperative axial neck pain and intraoperative blood loss. We evaluate a potentially less invasive, muscle splitting approach for atlantoaxial fusion in a cadaver model. METHODS: A technical feasibility study was performed in a human cadaveric specimen with standard surgical instruments and an operating microscope. Surgically relevant anatomical structures as well as final exposure of the C1, C1/C2 and C2 screw entry points are demonstrated. RESULTS: Following a midline skin incision, blunt mobilization and downward retraction of the trapezius and splenius capitis muscle is followed by a longitudinal split of the semispinalis capitis muscle. At the lower border of the rectus capitis posterior major and the obliquus capitis inferior muscle the entry points for C1 lateral mass, C1/C2 transarticular and C2 pedicle screw are exposed. CONCLUSION: Minimal invasive splitting of the semispinalis capitis muscle allows adequate exposure of the screw entry points of C1, C1/C2 and C2 while preserving the intrinsic muscles of the back at the craniocervical junction.

Extended exposure of the petroclival junction: The combined anterior transpetrosal and subtemporal/transcavernous approach.

BACKGROUND: The combined anterior transpetrosal and subtemporal/transcavernous (atsta) approach to the petroclival junction provides a wide exposure facilitating resection of large tumor lesions such as petroclival mengiomas, chondrosarcomas, or chordomas. In this article we provide technical instructions on the approach with anatomical consideration and a literature review of previous applications of this approach. METHODS: The combined approach was performed in two cadaveric specimen and relevant anatomical aspects were studied. Additionally, the authors performed a review of the literature focusing on indications, neurologic outcome, and complications associated with the technique. RESULTS: A combined atsta approach offers a wide exposure of the crus cerebrum, pons, basal temporal lobe, cranial nerves III to VII/VIII, posterior cerebral artery (PCA), superior cerebellar artery (SCA), basilar artery (BA), anterior inferior cerebellar artery (AICA), and posterior communicating artery (Pcom). It has been successfully applied with acceptable morbidity and mortality rates, mainly for (spheno-) petroclival meningiomas. CONCLUSION: The combined approach studied here is a useful skull base approach to the petroclival junction and can be applied to treat large or complex pathologies of the region. Detailed anatomical knowledge is essential.