summary Neurofibromatosis is an autosomal dominant disorder caused by a mutation in the NF1 gene that codes for the neurofibromin protein that typically presents with skin lesions, lower and upper extremity deformities, and spinal involvement. Diagnosis is made with the NIH Consensus Development Conference Statement criteria with the presence of a combination of cafe-au-lait spots, neurofibromas, freckling in axillary/inguinal region, optic glioma, lisch nodules, and the presence of a 1st degree relative with NF-1. Treatment depends on presence and severity of forearm, lower extremity or spinal deformity. Epidemiology Incidence 1:3,000 births for NF1 Anatomic location extremity deformities congenital anterolateral bowing and pseudoarthrosis of tibia/ fibula and forearm hemihypertrophy spine involvement scoliosis & kyphosis atlantoaxial instability Etiology Genetics autosomal dominant (AD) mutation in NF1 gene on chromosome 17q11.2 codes for neurofibromin protein negatively regulates Ras signaling pathway neurofibromin deficiency leads to increased Ras activity affects Ras-dependent MAPK activity which is essential for osteoclast function and survival neurofibromatosis is the most common genetic disorder caused by a new mutation of a single gene Associated conditions scoliosis anterolateral bowing of tibia bowing of forearm bones with obliteration of medullary cavity ulnar pseudoarthrosis radius pseudoarthrosis neoplasias Diagnosis Diagnostic criteria according to the NIH Consensus Development Conference Statement (1987) the diagnostic criteria for NF-1 are met in an individual if two or more of the following are found six or more café-au-lait macules over 5 mm in greatest diameter in prepubertal individuals and over 15 mm in postpubertal individuals. two or more neurofibromas of any type or one plexiform neurofibroma. freckling in the axillary or inguinal region. optic glioma. two or more Lisch nodules (iris hamartomas). a distinctive osseous lesion such as sphenoid dysplasia or thinning of long bone cortex with or without pseudarthrosis. a first-degree relative (parent, sibling, or offspring) with NF-1 by the above criteria.is based on presence of both Classification NF1 (von Recklinghaussen disease) most common NF2 associated with bilateral vestibular schwannomas Segmental NF features of NF1 but involving a single body segment Presentation General Presentation often presents with anterolateral bowing of tibia often presents with radial bowing Physical exam verrucous hyperplasia hemihypertrophy cafe-au-lait spots axillary freckling scoliosis anterolateral bowing or pseudoarthrosis of tibia dermal Plexiform-type neurofibroma may be seen Lisch nodules are benign pigmented hamartomas of the iris Neoplasias (Neurofibromatosis) Neurofibromas (plexiform-type) is pathognomonic for NF1 present in 4% of NF1 may be dermal or in deep tissues often associated with limb overgrowth can undergo malignant transformation to neurofibrosarcoma Wilms Tumor Scoliosis (Neurofibromatosis) Introduction spine is most common site of skeletal involvement in NF-1 scoliosis is NOT associated with NF-2 can take two forms idiopathic-like form (nondystrophic) longer curve and treatment resembles that for idiopathic scoliosis dystrophic form curve is typically thoracic kyphoscoliosis with a short segmented and sharp curve with distorted ribs and vertebrae usually recognized earlier than nondystrophic form generally characterized by a sharp angular curve involving 4 to 6 vertebrae Imaging radiographs show vertebral scalloping penciling of ribs (penciling of 3 or more ribs is a poor prognostic finding and associated with rapid curve progression) enlarged foramina MRI always obtain preoperative MRI to identify dural ectasia and dumbbell lesion (neurofibroma on nerve root) paraspinal masses are useful to distinguish from idiopathic scoliosis Treatment nonoperative observation vs. bracing bracing is not effective for dystrophic form nondystrophic scoliosis in NF is treated like adolescent idiopathic scoliosis operative decompression, anterior spinal fusion (ASF) & posterior (PSF) with instrumentation indications dystrophic scoliosis perform early in young children (< 7 yrs) with dystrophic curves complications high rate of pseudoarthrosis with PSF alone (40%) pseudoarthrosis rate still high with ASF&PSF (10%) some recommend augmenting the PSF with repeat iliac crest bone grafting 6 months after the primary surgery Anterolateral Tibial Bowing (Neurofibromatosis) Introduction epidemiology anterolateral bowing is often associated with neurofibromatosis (NF1) 50% with anterolateral bowing have NF1 10% of NF1 have anterolateral bowing pathophysiology may progress to pseudoarthrosis differentials for tibia bowing anteromedial associated with fibular hemimelia and congenital loss of lateral rays of the foot posteromedial usually congenital due to abnormal intrauterine positioning dorsiflexed foot pressed against anterior tibia will develop leg length discrepancy associated with calcaneovalgus deformity Imaging radiographs obtain AP and lateral of tib/fib Treatment nonoperative bracing in total contact orthosis indications bowing without pseudoarthrosis or fracture (goal is to prevent further bowing and fractures) spontaneous remodeling is not expected osteotomy for bowing alone is contraindicated operative bone grafting with surgical fixation indications in bowing with pseudoarthrosis or fracture amputation with prosthesis fitting indications three failed surgical attempts Syme's often superior to BKA due to atrophic and scarred calf muscle in these patients Techniques intramedullary nailing with bone grafting resect pseudoarthrosis insert Charnley-Williams rod antegrade through resection site, then retrograde through the heel < 4 y.o., extend fixation to calcaneus 5-10 y.o., extend fixation to talus 2 yrs. postop, typically a 2nd surgery to push rod proximally to free the ankle joint free fibular graft often need to take fibula from contralateral side because ilpsilateral fibula is not normal Illizarov's external fixation Prognosis Studies show between 8-10 years of decreased life expectancy compared to general population High incidence of malignancy and hypertension
QUESTIONS 1 of 27 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ18.38) A child is found to have axillary and inguinal freckling, scoliosis, and hamartomas within his iris. Which of the following pairs the inheritance pattern of the condition with the leg abnormality found in the condition? QID: 212934 FIGURES: A B C Type & Select Correct Answer 1 Autosomal dominant; Figure B 72% (1130/1574) 2 Autosomal recessive; Figure B 12% (195/1574) 3 X-linked recessive; Figure A 4% (56/1574) 4 Autosomal dominant; Figure C 6% (90/1574) 5 Autosomal recessive; Figure A 6% (91/1574) L 2 Question Complexity A Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic (OBQ18.49) A 6-year-old boy with neurofibromatosis type 1 returns for follow-up of the condition shown in Figures A and B. The patient has attempted bracing with a knee-ankle-foot orthosis and long leg casting but has not had any radiographic improvement. What is the best next step in management? QID: 212945 FIGURES: A B Type & Select Correct Answer 1 Continued bracing 6% (109/1816) 2 Bone stimulator 2% (35/1816) 3 Intramedullary nailing 4% (79/1816) 4 Resection of pseudoarthrosis , bone grafting, and intramedullary nailing 86% (1564/1816) 5 Amputation 1% (17/1816) L 2 Question Complexity A Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (OBQ18.55) A 4-year-old refugee patient presents with multiple orthopedic complaints. To date, the patient has not seen any specialists or received any treatment with regards to their symptoms. Radiographs are shown in Figures A-C. Based on the diagnosis, what other manifestations may also be present? QID: 212951 FIGURES: A B C Type & Select Correct Answer 1 Radial head subluxation 17% (310/1827) 2 Excessive glenoid retroversion 3% (58/1827) 3 Absence of the anterior cruciate ligament 13% (246/1827) 4 Hemihypertrophy 32% (591/1827) 5 Developmental dysplasia of the hip 34% (617/1827) L 5 Question Complexity A Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (SBQ13PE.55) A 4-year-old boy is referred to your office for evaluation of a progressive lower extremity deformity. AP radiographs are shown in Figure A. All of the following may also be found on physical examination EXCEPT: QID: 5127 FIGURES: A B C D E F Type & Select Correct Answer 1 Figure B 8% (128/1669) 2 Figure C 5% (83/1669) 3 Figure D 4% (66/1669) 4 Figure E 76% (1264/1669) 5 Figure F 7% (122/1669) N/A Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (SBQ13PE.20) A patient presents with scoliosis associated with neurofibromatosis. In addition to intracanal neurofibromas, which of the following is commonly associated with this condition, and should be assessed by MRI of the spinal axis preoperatively? QID: 4987 Type & Select Correct Answer 1 Syrinx 26% (1104/4225) 2 Hemivertebra 4% (176/4225) 3 Dural ectasia 55% (2344/4225) 4 Diastematomyelia 7% (311/4225) 5 Spina bifida occulta 7% (275/4225) L 4 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ10.142) All of the following are associated with neurofibromatosis EXCEPT: QID: 3230 Type & Select Correct Answer 1 Smooth bordered café-au-lait spots 3% (85/2546) 2 Posterior-medial bowing of the tibia 81% (2069/2546) 3 Short, sharp dystrophic scoliosis 10% (262/2546) 4 Cutaneous neuromas 2% (56/2546) 5 Autosomal dominant transmission from mutated neurofibromin gene 3% (69/2546) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review Tested Concept Review Full Topic (OBQ08.25) A 3-year-old boy presents with a leg deformity and multiple skin lesions. Lisch nodules were found on ophthalmologic exam. A clinical photograph and radiographs are shown in Figure A and B. What is the inheritance pattern and mutation that encodes for this condition. QID: 411 FIGURES: A B Type & Select Correct Answer 1 autosomal dominant; mutation in NF1 gene that codes for neurofibromin protein 84% (2416/2860) 2 autosomal recessive; mutation in NF1 gene that codes for neurofibromin protein 12% (332/2860) 3 autosomal dominant; mutation of FGFR3 (fibroblast growth factor recepter) 1% (40/2860) 4 autosomal recessive; mutation of FGFR3 (fibroblast growth factor recepter) 1% (31/2860) 5 autosomal dominant; mutation of GS alpha protein 1% (20/2860) L 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ08.226) A 60-year-old man presents with the hand condition shown in Figure A. The mass is resected with gross pathology and histopathology representations displayed in Figures B and C, respectively. What is the altered genetic etiology of this condition? QID: 612 FIGURES: A B C Type & Select Correct Answer 1 COMP 4% (42/1185) 2 Fibrillin 10% (116/1185) 3 Neurofibromin 77% (915/1185) 4 COL2A1 6% (66/1185) 5 RUNX2/CBFA1 3% (37/1185) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic (OBQ08.37) A 3-year-old boy presents with a forearm deformity. Radiographs are shown in Figure A. Ophthalmologic exam shows the lesion seen in Figure B. These finding are most consistent with which of the following conditions? QID: 423 FIGURES: A B Type & Select Correct Answer 1 Achondroplasia 0% (3/1567) 2 Fibrous dysplasia 2% (26/1567) 3 Osteogenesis imperfecta 8% (128/1567) 4 Neurofibromatosis Type 1 86% (1355/1567) 5 Ollier's disease 3% (45/1567) L 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK This is an AAOS Self Assessment Exam (SAE) question. Orthobullets was not involved in the editorial process and does not have the ability to alter the question. If you prefer to hide SAE questions, simply turn them off in your Learning Goals. (SAE07PE.91) What is the most important sign of impending modulation with rapid progression of a spinal deformity in neurofibromatosis? QID: 6151 Type & Select Correct Answer 1 Apical curve rotation 15% (49/323) 2 Anterior vertebral body erosions 7% (24/323) 3 Cervical spine involvement 5% (17/323) 4 Penciling of three or more ribs 38% (122/323) 5 Curve magnitude of more than 50 degrees 34% (111/323) L 4 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic This is an AAOS Self Assessment Exam (SAE) question. Orthobullets was not involved in the editorial process and does not have the ability to alter the question. If you prefer to hide SAE questions, simply turn them off in your Learning Goals. (SAE07PE.34) A 10-year-old girl who is Risser stage 0 has back deformity associated with neurofibromatosis type 1 (NF1). She has no back pain. Examination shows multiple cafe-au-lait nevi with normal lower extremity neurologic function and reflexes. Standing radiographs of the spine show a short 50-degree right thoracic scoliosis with a kyphotic deformity of 55 degrees (apex T8). A 10-degree progression in scoliosis has occurred during the past 1 year. There is no cervical deformity. MRI shows mild dural ectasia, primarily in the upper lumbar region. Management should consist of QID: 6094 Type & Select Correct Answer 1 observation with repeat radiographs in 6 months. 3% (17/491) 2 a thoracolumbosacral orthosis (TLSO). 16% (80/491) 3 in situ posterior spinal fusion without instrumentation, followed by full-time TLSO bracing. 7% (36/491) 4 anterior spinal convex hemiepiphysiodesis. 4% (18/491) 5 combined anterior and posterior spinal arthrodesis with instrumentation. 68% (335/491) L 2 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic (OBQ06.202) A 3-year-old boy presents with the skin lesion seen in Figure A and a leg deformity. Radiographs are shown in Figure B. What is the most appropriate first step in treatment? QID: 213 FIGURES: A B Type & Select Correct Answer 1 observation 21% (594/2763) 2 bracing in total contact orthosis 72% (2000/2763) 3 intramedullary nailing with bone grafting 3% (74/2763) 4 free fibular graft from contralateral side 0% (12/2763) 5 external fixation using Illizarov techniques 2% (66/2763) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review Tested Concept Review Full Topic (OBQ05.43) The diagnostic criteria for neurofibromatosis type I includes all of the following EXCEPT: QID: 79 Type & Select Correct Answer 1 2 or more neurofibromas 1% (17/1218) 2 6 or more cafe-au-lait macules 2% (20/1218) 3 2 or more Lisch nodules 3% (32/1218) 4 freckling on the plantar surface of the feet 81% (990/1218) 5 optic glioma 13% (156/1218) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (SBQ04PE.41) A 3-year-old male is evaluated in your office. On examination he is found to have several pigmented cutaneous lesions and hamartomas of the iris. His right leg was previously treated with both a knee-ankle-foot orthotic and long-leg casting for approximately 9 months. His most recent radiographs are seen in Figures A and B. What is the next best treatment? QID: 2226 FIGURES: A B Type & Select Correct Answer 1 Bone stimulator 2% (34/1702) 2 Continue bracing 9% (145/1702) 3 Syme amputation 1% (11/1702) 4 Resection of pseudoarthrosis with bone grafting and surgical fixation 87% (1482/1702) 5 Below knee amputation 1% (23/1702) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (OBQ04.74) All of the following are clinical features of neurofibromatosis type I (NF-I) EXCEPT? QID: 1179 Type & Select Correct Answer 1 freckling in the axillae 4% (29/794) 2 optic glioma 10% (78/794) 3 2 or more Lisch nodules 2% (17/794) 4 talipes equinus 83% (661/794) 5 cafe' au lait spots 1% (7/794) L 2 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic
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