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Peripheral nerve injuries due to osteochondromas: analysis of 20 cases and review of the literature Clinical article Selçuk Göçmen, M.D.,1 Ali Kıvanç Topuz, M.D.,1 Cem Atabey, M.D.,1 Hakan Şimşek, M.D.,1 Kenan Keklikçi, M.D., 2 and Osman Rodop, M.D. 2 Departments of 1Neurosurgery and 2Orthopedics, Gulhane Military Medical Academy, Haydarpasa Training Hospital, Istanbul, Turkey Object. Nerve compressions due to osteochondromas are extremely rare. The aim of this retrospective study was to investigate the mechanisms, diagnostic evaluations, and treatment of nerve lesions due to osteochondromas, and to review the literature. Methods. The authors retrospectively reviewed their clinic data archive from 1998 through 2008, and 20 patients who were operated on due to peripheral nerve injuries caused by osseous growth were enrolled in the study. Patients’ age, duration of symptoms, localizations, intraoperative findings, and modified British Medical Research Council (MRC) and electromyography data obtained from hospital records were evaluated. The literature on this topic available in PubMed was also reviewed. All 20 patients underwent surgery, which consisted of tumor excision performed by orthopedic surgeons and nerve decompression performed by neurosurgeons. Results. There were 17 men and 3 women included in the study, with a mean age of 21 years (range 18–25 years). Three patients had multiple hereditary exostoses, and 17 had a solitary exostosis. All of the patients underwent en bloc resection. The most common lesion site was the distal femur (45%). The peroneal and posterior tibial nerves were the structures that were affected the most frequently. The mean follow-up was 3.9 years (range 2–7 years). After the surgery, all patients (100%) experienced good sensory recovery (modified MRC Grade S4 or S5). Conclusions. To the authors’ knowledge, no large series have reported peripheral nerve compression due to exostoses. The authors have several recommendations as a result of their findings. First, all patients with peripheral nerve compression due to an osteochondroma should undergo surgery. Second, preoperative electromyographic examinations and radiographic evaluation, consisting of MRI and CT to provide optimal information about the lesion, are crucially important. Third, immediate treatment is mandatory to regain the best possible recovery. And fourth, performing nerve decompression first and en bloc resection of osteochondroma consecutively in a multidisciplinary fashion is strongly recommended to avoid peripheral nerve injury. (http://thejns.org/doi/abs/10.3171/2013.11.JNS13310)
O
Key Words • osteochondroma • exostoses • nerve compression • peripheral nerve • electromyography steochondroma,
also known as osteocartilaginous exostosis, is the most common of all benign bone tumors. There are 2 types of osteochondroma, solitary osteochondroma and multiple hereditary exostoses (MHE).18 In the MHE type, there is a strong familial incidence, and it is an autosomal dominant disorder with variable penetrance. Osteochondromas can arise in any bone that has undergone endochondral ossification, but they are more commonly associated with the metaphyseal regions of the lower femur, upper tibia, and upper humerus.15 Clinical symptoms can result from mechanical irritation or compression of adjacent structures (such as soft tissues, bone, internal organs, peripheral nerves, spinal cord, and blood vessels), fracture, and malignant trans-
formation.44 Nerves can be damaged by direct trauma, pressure injuries, fractures, ischemic neuropathies, spontaneous hematomas, cysts arising from the joint, entrapments, and neoplasms. Nerve compression syndromes are the neurological symptom complexes caused by the mechanical or dynamic compression of a segment of a single nerve at specific sites as it passes through a narrow fibroosseous tunnel or an opening in a fibrous or muscular structure.21 In the literature, only individual cases of peripheral nerve compression secondary to solitary osteochondromas are available.2,4–6,8–20,22–34,36–38,40–47 This case series is the largest series of peripheral nerve compressions due to solitary osteochondromas, and our aim in this retrospective study was to investigate the mechanisms, diagnostic
Abbreviations used in this paper: EMG = electromyography; MHE = multiple hereditary exostoses; MRC = Medical Research Council.
This article contains some figures that are displayed in color online but in black-and-white in the print edition.
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S. Göçmen et al. evaluations, and treatment of nerve lesions due to osteochondromas, and to review the literature.
Clinical Data Review
Methods
Twenty patients with osteochondroma were admitted to Gulhane Military Medical Academy (Haydarpasa Training Hospital Departments of Neurosurgery and Orthopedic Surgery) for management of exostoses between June 1998 and December 2008. Medical records and diagnostic imaging of these patients were obtained and reviewed (Table 1). Exostoses were classified as solitary or associated with a history of MHE. Medical records were evaluated for age, initial/chief complaint, duration of symptoms, and symptoms indicative of neural structure compression (peripheral nerve injuries). Physical examinations were reviewed for neurological deficits (modified British Medical Research Council [MRC] grade35), palpable mass, and other pertinent findings. Electrophysiological studies, plain radiography, CT, and MRI in the preoperative and postoperative periods were available in all patients. Method of treatment, surgical margins, histopathology, and complications were evaluated. Diagnosis was confirmed histopathologically. Follow-up evaluations were reviewed for progression or recurrence of symptoms, and tumor enlargement or recurrence. Literature Review
The literature was reviewed using the PubMed data-
base and bibliographies of published papers. Cases were reviewed for clinical details including age, symptoms, method of treatment, resolution of symptoms, and tumor recurrence. The nerve injury and site of origin on the bone of the exostoses were recorded. Surgical Data
In our patient series, the surgical indication was peripheral nerve compression due to a solitary osteochondroma. All patients underwent surgery for neurological involvement via a team-based approach, consisting of a neurosurgeon first exploring and preserving the nerve, followed by tumor resection by an orthopedic surgeon. Our experiences and intraoperative observations show that there are 2 main categories of peripheral nerve compression due to osteochondromas: a direct extrinsic pressure to the nerve, and growth of the osteochondroma causing circumferential ring formation that surrounds the peripheral nerve (Fig. 1). Direct extrinsic compression comprises 2 subtypes: integrity of the nerve preserved, and integrity of the nerve impaired (splitting the nerve). As another point of interest, the neurovascular structures were found to be adherent to the osteochondroma by a fibrous band. Therefore, we had to carefully dissect the fibrous band and release the neurovascular structures before the tumor was removed to avoid surgery-related severe neurovascular complications during tumor excision. After decompression surgery, it was observed during the follow-up period that patients recovered completely. Complete removal of the solitary exostoses provided a
TABLE 1: Characteristics of the 20 patients with peripheral nerve injuries due to osteochondromas Case No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
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Age (yrs), Type of Sex Osteochondroma 20, M 21, M 21, M 25, M 20, M 22, F 21, M 21, M 21, M 18, M 21, M 20, M 22, M 22, M 21, M 20, M 20, M 18, F 24, F 22, M
solitary solitary solitary solitary solitary solitary solitary solitary solitary MHE MHE solitary solitary solitary solitary solitary solitary MHE solitary solitary
Location of Exostoses
Nerve Injury/ Chief Complaint
Results
lt distal femur rt proximal humerus lt distal femur lt proximal femur lt proximal tibia rt clavicle rt fibula head lt proximal radius rt distal femur rt distal femur lt distal femur rt distal femur lt fibula head lt proximal humerus lt proximal humerus lt distal fibula rt fibula head lt distal femur lt distal femur lt distal femur
peroneal/posterior tibial radial peroneal/posterior tibial sciatic peroneal brachial plexus peroneal radial peroneal/posterior tibial peroneal/posterior tibial peroneal/posterior tibial peroneal/posterior tibial peroneal radial radial peroneal peroneal peroneal/posterior tibial peroneal/posterior tibial peroneal/posterior tibial
no symptoms 2 yrs no symptoms 5 yrs no symptoms 6 yrs no symptoms 2 yrs no symptoms 4 yrs no symptoms 5 yrs no symptoms 4 yrs no symptoms 5 yrs no symptoms 4 yrs recurrence at 3 yrs postop; no symptoms 4 yrs after 2nd op no symptoms 4 yrs no symptoms 4 yrs no symptoms 3 yrs no symptoms 4 yrs no symptoms 3 yrs no symptoms 5 yrs no symptoms 3 yrs no symptoms 2 yrs no symptoms 3 yrs no symptoms 3 yrs
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Nerve injuries due to osteochondromas In total, all patients (100%) improved to modified MRC Grade M4 or M5 motor function during the postoperative period. Several patients recovered motor function within hours or days following surgery. The majority of patients recovered in several months. The results of the sensory improvement were similar to that of motor dysfunctions. Nineteen of 20 patients had fair sensory functions (modified MRC Grade S2 or S3). Only 1 patient had no sensation (modified MRC Grade S0). After surgery, all patients (100%) had good sensory recovery (modified MRC Grade S4 or S5). Electromyography Data
Fig. 1. Anteroposterior plain radiographs (left column) and illustrations (right column) show the 2 main categories of peripheral nerve compression due to osteochondromas. A: Direct extrinsic pressure to the nerve (arrow). B: Growth of the osteochondroma causing circumferential ring formation that surrounds peripheral nerves (arrow). Copyright Selçuk Göçmen. Published with permission.
cure; however, 1 patient with MHE experienced tumor recurrence 3 years after resection.
Patient Characteristics
Results
Three female and 17 male patients were treated at our institution (Table 1). Three patients had MHE and 17 had a solitary exostosis. The mean age was 21 years (range 18–25 years). Patients with MHE were younger than patients with solitary exostoses, as the mean age for patients with MHE was 19 years (range 18–21 years) compared with 21.3 years (range 20–25 years) for patients with solitary exostosis. The mean follow-up duration was 3.9 years (range 2–7 years).
Sensorimotor Outcome
The sensorimotor recovery was scored on a scale ranging from 0 to 5 points, as recommended by the modified MRC. Preoperatively, all patients had weakness and sensory disturbances. Nineteen of 20 patients had fair motor functions (modified MRC Grade M2–M3; Table 2). Only 1 patient had total loss of motor function in the peroneal nerve–innervated musculature (modified MRC Grade M0). All of the patients (100%) who had motor dysfunction preoperatively were noted to experience improvement in their motor function following surgery (p < 0.01). Only 1 patient had no motor function preoperatively, but in the postoperative follow-up period he showed improvement in motor function to modified MRC Grade M4.
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The electromyography (EMG) studies were repeated after surgery for the patients with impaired EMG findings, consisting of slow conduction velocities and reduced motor and sensory nerve action potential in the preoperative periods. Sixteen of the 20 patients exhibited an incomplete axonal loss pattern, 3 had a mixed pattern, and 1 had a pure conduction block pattern. Electromyography performed after resection of the exostoses suggested nerve recovery and remyelination. In our series, the majority of the lesions were located in the distal femur (45%), followed by the fibula (20%), proximal humerus (15%), proximal tibia (5%), proximal femur (5%), clavicle (5%), and radius (5%; Table 3, Figs. 2–6). The peroneal and posterior tibial nerves were the most commonly affected nerve structures (Fig. 7). Patients with osteocartilaginous exostoses of the proximal humerus and radius had palsies of the radial nerves. The majority of the peripheral nerve injuries due to osteochondromas (50%) were located in the left lower extremities.
Patients With MHE
Two (66.7%) of 3 patients with MHE had a painful mass and weakness as the initial complaint. All patients with MHE had symptoms or findings on physical examination consistent with neural structure compression. All the lesions in these patients were modified MRC M3 levels before the operation (Table 2, Fig. 8). The motor scores of all the patients were M5 levels after the operation. One patient who experienced tumor recurrence 3 years after surgery reported pain at follow-up evaluation. This patient underwent repeat excision of the lesion by the orthopedic surgeons. There was no tumor recurrence after the second procedure during his 4-year follow-up. Two of 3 patients had no complications, no tumor recurrence, and had complete resolution of symptoms after a mean follow-up of 3 years (range 2–4 years).
Patients With Solitary Lesions
Eight (47.1%) of 17 patients with solitary lesions had a painful mass and weakness, whereas 6 (35.3%) had only a mass and weakness. Three (17.7%) of 17 patients had pain and weakness as their initial complaint. All patients with solitary lesions had symptoms or findings on physical examination consistent with neural structure compression. Nine (53%) of 17 patients had M3-level motor scores and 8 (47.1%) had M2-level motor scores before the operation. These patients were treated surgically with lesional resec1107
S. Göçmen et al. TABLE 2: Sensorimotor outcomes after surgery according to the modified MRC scale Motor Recovery Outcomes
M0
preop findings postop findings
1
M1
M2
M3
8
11
tion and nerve decompression. There were no complications, no tumor recurrence, and complete resolution of symptoms after a mean follow-up of 3.8 years (range 2–6 years). We observed good recovery (M5) in all of these patients (Table 2). Literature Review
The review of the literature revealed 41 cases of peripheral nerve compression secondary to solitary osteochondromas. The age of the patients in this review ranged from 3 to 69 years, and most patients were less than 25 years old (mean 23.7 years). Most patients were male (male to female ratio of 25:9). Multiple hereditary exostoses were positive in 12 patients (32.4%) in 37 documented cases. The proximal fibula was the most frequently attacked area in 59 patients (36.6%). The peroneal nerve had the largest entrapment rate (46.6%). The proximal humerus was the most frequently afflicted region in the upper extremities (50%); it was detected in 10 cases. Forty-nine of 54 patients who underwent surgery experienced good outcomes. The outcomes of the remaining 3 cases were poor and 2 cases were unknown. Gray et al. reported the first splitting of a nerve by an osteochondroma.12
Sensory Recovery M4
M5
9
11
S0 1
S1
S2
S3
9
10
S4
S5
10
10
consistent with neural structure compression. This study provides the largest clinical series of osteochondromas due to peripheral nerve compression from a single institution. Solitary osteochondromas have their highest incidence within the 2nd and 3rd decades of life, with a predominance of males affected.27 The ages and gender distributions of our patients with solitary lesions were consistent with those in the literature. Multiple osteochondromas occur as part of a rare familial syndrome with autosomal dominant inheritance (MHE).44 Three patients had MHE in our cases. Osteochondromas may be found in nearly every bone, with the exception of the calvaria.39 The most frequent sites of involvement include the knees, humerus, hips, scapula and ribs, wrists, ankles, elbows, hands, feet, and pelvis.39 Osteochondromas of the peripheral skeleton can cause nerve compression with consecutive entrapment neuropathies or nerve palsies. The peroneal nerve or radial nerve is the most frequently affected structure. Motor weakness or peroneal nerve palsy can occur as sequelae of chronic neural compression by osteochondromas lo-
Discussion
Osteochondroma, or osteocartilaginous exostosis, is a benign cartilage-forming lesion that comprises 10%–15% of all bone tumors.44 Osteochondromas are usually asymptomatic. However, several potential tumor-related complications can occur, especially in lesions with marked extent or location in critical anatomical sites.44 Skeletal complications including deformity, joint dysfunction, fracture, and malignant degeneration are the most common.38 Nonskeletal extrinsic complications due to mass effect on the adjacent tissues, including soft tissue, vascular, and neurological structures, are relatively rare. Nerve compression is extremely rare, present in less than 1% of all cases.8,24,38 However, the majority of the patients in our series and cases identified in the literature had presenting symptoms TABLE 3: Lesion localizations and nerve compressions Localization
Nerve Entrapment
Value (%)
distal femur fibula proximal humerus proximal tibia proximal femur clavicle radius
peroneal/posterior tibial peroneal radial peroneal sciatic brachial plexus radial
9 (45) 4 (20) 3 (15) 1 (5) 1 (5) 1 (5) 1 (5)
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Fig. 2. Case 5. A: Lateral plain radiograph shows a bone lesion (arrow) before surgery. B: Sagittal MR image shows a bone lesion attached to the proximal tibia by a pedicle (arrow). C: Photograph of excised bone lesion with its pedicle.
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Fig. 3. Case 6. A: An anteroposterior plain radiograph reveals an osteochondroma (arrow) of the right clavicle that was compressing the brachial plexus. B: Axial CT scan identifying the lesion (arrow). C and D: Coronal (C) and axial (D) MR images of the same patient showing the lesion (arrow).
cated at the proximal tibiofibular articulation.39,44 Palsies of the axillary and radial nerves have been described in patients with osteocartilaginous exostoses of the proximal humerus.39,44 In our series, the majority of the lesions were located in the distal femur (45%), followed by the fibula (20%), proximal humerus (15%), proximal tibia (5%), proximal femur (5%), clavicle (5%), and radius (5%). In our cases the peroneal and posterior tibial nerves were the most frequently afflicted peripheral nerves. Osteochondromas may impinge on adjacent soft-tissue structures such as tendons, muscles, nerves, and vascular structures. Neurological complications are due to direct impingement upon adjacent nerves by an osteochondroma.39 Therefore, nerve decompression is performed very carefully. Teamwork is important to plan and perform a complete removal of the exostosis. First, the nerve should be explored and preserved by a neurosurgeon, and then an orthopedist should resect the tumor. If the nerve is not first explored, the patient becomes susceptible to severe and irreversible nerve injury. In the second type of lesion (Fig. 1B), nerve injuries are more common. Not only histological examination, but also electrophysiological studies can provide the definitive diagnosis. However, our experiences and intraoperative observations show that there is not only a direct extrinsic pressure to the nerve, but also circumferential ringlike tumor tissue that surrounds the nerve, resulting from the growth of an osteochondroma. The shape and size of the exostosis is variable. Some are pedunculated with a globose, “mushroom,” or “cauliflower-like” summit, or (smaller exostoses) with a sharp “thornlike” or “coat-hanger” appearance.3 Others have a broad sessile implant. The pedunculated exostoses are usually directed toward the diaphysis. Rarely, the exostosis can reach large sizes, which per se do not prove malignancy.3 Plain radiography is a very practical tool to determine J Neurosurg / Volume 120 / May 2014
Fig. 4. Case 7. A and B: Anteroposterior (A) and lateral (B) plain radiographs show the tumor (arrows) that arose from the proximal fibula, which was found to be an osteochondroma. C: Axial CT scans of the same lesion (arrows).
Fig. 5. Case 14. A and B: Anteroposterior plain radiograph (A) and axial CT scan (B) reveal an osteochondroma of the proximal humerus that was compressing the radial nerve. C and D: Intraoperative image of the lesion (C) and the tumor that was removed surgically (D).
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Fig. 6. Case 17. A: Anteroposterior plain radiograph showing a proximal fibula osteochondroma. B and C: Sagittal (B) and axial (C) MR images of the lesion.
the number, location, and morphology of the exostoses, and to document complications such as cosmetic and osseous deformities and fracture.39 Osteochondromas are best visualized on CT rather than MRI, as the bony nature of the lesions is most clearly delineated.7 Magnetic resonance imaging is the examination method of choice for detecting complications such as bursa formation, vascular compromise, tendon or nerve compression, and malignant transformation.39 Magnetic resonance imaging is valuable for verifying peripheral compressive neuropathies caused by osteocartilaginous exostoses.44 Changes in signal intensity, size, or position of the involved peripheral nerve have been shown to represent suggestive MRI findings of compressive and entrapment neuropathies.44 On MR images, osteochondromas are observed as an isointense signal with a low-signal rim produced by the cortical bone.7 Preoperative MR images and CT scans should be examined carefully to provide optimal information about the lesion and aid treatment options. All the patients in this series underwent electrophysiological examinations. A needle electromyographic study usually reveals a pattern of abnormality consistent with a lesion. Surgical findings determine adhesion of the involved nerves. The final diagnosis has to be made using histopathological investigation.
The general surgical indications for benign bone growths are cosmetic defect, exostosis in a location at risk to repetitive trauma, increased risk of the exostoses to fracture, neurological involvement, impairment of the articular range of motion, and suspicion of malignancy.8 Total en bloc excision of the tumor is the treatment of choice.1 Other investigators have similarly reported a higher recurrence rate after curettage and bone grafting (41%) as opposed to resection (7%).1 After decompression surgery, all of our patients described above reported almost complete recovery neurologically, and electrophysiological tests were normalized thereafter. The surgeon must be cognizant that recurrence is common after incomplete removal of the lesion. Complete functional recovery is the goal, and delays in diagnosis and treatment can result in irreversible neurological impairments. Therefore, a teambased approach consisting of a neurosurgeon first exploring and preserving the nerve, followed by lesion resection by an orthopedic surgeon, offers the safest and optimal strategy. We believe that advanced axonal loss at the time of diagnosis was responsible for the unsatisfactory outcome, which emphasizes the importance of early diagnosis and treatment. Osteochondromas do not affect patient life expectancy. Malignant transformation is the most feared com-
Fig. 7. Case 13. A: Photograph of the operative plan. The lesion, caput fibula (CF), and incision lines are marked. B: The lesion was compressing the bifurcation of a peroneal nerve. The lesion was removed in 2 parts. A small piece of the lesion is noted in the photograph. The white arrow indicates the common peroneal nerve, the thick yellow arrow indicates the superficial peroneal nerve, the thin yellow arrow indicates the deep branch of the peroneal nerve, the red arrow shows the peroneus longus muscle, and the blue arrow shows a small piece of the lesion. C: Photograph of the resected tumor in 2 pieces.
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Nerve injuries due to osteochondromas include the following. Conception and design: Göçmen, Topuz, Atabey, Şimşek. Acquisition of data: Göçmen, Topuz. Analysis and interpretation of data: Göçmen. Drafting the article: Göçmen, Şim şek. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Göçmen. Administrative/technical/material support: Göçmen. Study supervision: Topuz, Atabey, Şimşek, Keklikçi, Rodop. References
Fig. 8. Case 10 with MHE. A: Anteroposterior plain radiograph shows bilateral osteochondromas of the distal femur (thin arrows) and left proximal tibia (wide arrow). B: Anteroposterior plain radiograph shows the proximal humerus with the osteochondroma (arrow). C and D: Axial (C) and coronal (D) MR images showing the lesion.
plication of osteochondroma. Osteochondromas may undergo sarcomatous transformation later in life, usually to a chondrosarcoma. Whereas the prevalence of complications in solitary osteochondromas has been estimated to be approximately 1%, this complication rate is higher with MHE, previously reported to be observed in as many as 25% of patients,39 although a lower prevalence of 3%–5% has been suggested.39 Malignant transformation was not observed in our series.
Conclusions
All patients with peripheral nerve compression due to an osteochondroma should undergo surgery. The nerve should always be decompressed and protected as a first step before the resection of the bone lesion. Preoperative radiographic evaluation should consist of MRI and CT to provide optimal information about the lesion and aid treatment options. Teamwork is crucial to plan and perform a complete removal of the exostoses. To avoid complications regarding further nerve injury and provide the optimal and safest strategy of management, we recommend a team-based approach consisting of a neurosurgeon first exploring and preserving the nerve, followed by lesion resection by an orthopedic surgeon. Disclosure The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. Author contributions to the study and manuscript preparation
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S. Göçmen et al. 20. Kim JY, Ihn YK, Kim JS, Chun KA, Sung MS, Cho KH: Nontraumatic peroneal nerve palsy: MRI findings. Clin Radiol 62: 58–64, 2007 21. Kim S, Choi JY, Huh YM, Song HT, Lee SA, Kim SM, et al: Role of magnetic resonance imaging in entrapment and compressive neuropathy—what, where, and how to see the peripheral nerves on the musculoskeletal magnetic resonance image: part 2. Upper extremity. Eur Radiol 17:509–522, 2007 22. Levin KH, Wilbourn AJ, Jones HR Jr: Childhood peroneal neuropathy from bone tumors. Pediatr Neurol 7:308–309, 1991 23. Maricevic A, Barisic I, Srsen D: Unusual “traction” exostosis of the femoral diaphysis with sciatic nerve compression. J Clin Rheumatol 16:94–95, 2010 24. Matsumoto K, Sumi H, Shimizu K: Tibial osteochondroma causing foot pain mimicking tarsal tunnel syndrome: a case report. J Foot Ankle Surg 44:159–162, 2005 25. Mnif H, Koubaa M, Zrig M, Zammel N, Abid A: Peroneal nerve palsy resulting from fibular head osteochondroma. Orthopedics 32:528, 2009 26. Montella BJ, O’Farrell DA, Furr WS, Harrelson JM: Fibular osteochondroma presenting as chronic ankle sprain. Foot Ankle Int 16:207–209, 1995 27. Montgomery PQ, Goddard NJ, Kemp HB: Solitary osteochondroma causing sural nerve entrapment neuropathy. J R Soc Med 82:761, 1989 28. Montskó P, Tarjányi J: [Paralysis of the peroneal nerve caused by multiple cartilagenous exostoses.] Magy Traumatol Orthop Helyreallito Seb 33:54–56, 1990 (Hungarian) 29. Oz O, Yücel M, Ulaş U, Eroğlu E, Odabaşi Z: Superficial radial neuropathy and brachioradial motor nerve palsy associated with proximal radius osteochondroma. Neurol Neurochir Pol 44:208–210, 2010 30. Paik NJ, Han TR, Lim SJ: Multiple peripheral nerve compressions related to malignantly transformed hereditary multiple exostoses. Muscle Nerve 23:1290–1294, 2000 31. Parker RG: Dorsal foot pain due to compression of the deep peroneal nerve by exostosis of the metatarsocuneiform joint. J Am Podiatr Med Assoc 95:455–458, 2005 32. Piton C, Fabre T, Lasseur E, André D, Geneste M, Durandeau A: [Common fibular nerve lesions. Etiology and treatment. Apropos of 146 cases with surgical treatment.] Rev Chir Orthop Repar Appar Mot 83:515–521, 1997 (Fr) 33. Rinaldi E: Peroneal paralysis due to exostosis of the fibula. Report of 2 cases. Ital J Orthop Traumatol 9:259–262, 1983 34. Ruth RM, Groves RJ: Synovial osteochondromatosis of the elbow presenting with ulnar nerve neuropathy. Am J Orthop 25:843–844, 1996 35. Secer HI, Solmaz I, Anik I, Izci Y, Duz B, Daneyemez MK, et al: Surgical outcomes of the brachial plexus lesions caused by
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gunshot wounds in adults. J Brachial Plex Peripher Nerve Inj 4:11, 2011 36. Theodorou SD, Karamitsos S, Tsouparopoulos D, Hatzipavlou AG: Rare complications of exostosis. Fractures and injury to the common peroneal nerve. Acta Orthop Belg 44:496–505, 1978 37. Tobias AM, Chang B: A rare brachial artery pseudoaneurysm 13 years after excision of a humeral osteochondroma. Ann Plast Surg 52:419–422, 2004 38. Turan Ilica A, Yasar E, Tuba Sanal H, Duran C, Guvenc I: Sciatic nerve compression due to femoral neck osteochondroma: MDCT and MR findings. Clin Rheumatol 27:403–404, 2008 39. Vanhoenacker FM, Van Hul W, Wuyts W, Willems PJ, De Schepper AM: Hereditary multiple exostoses: from genetics to clinical syndrome and complications. Eur J Radiol 40:208– 217, 2001 40. Waldschmidt U, Slongo T: An unusual cause of paralysis of the peroneal nerve—a case report. J Pediatr Surg 45:259–261, 2010 41. Watson LW, Torch MA: Peroneal nerve palsy secondary to compression from an osteochondroma. Orthopedics 16:707– 710, 1993 42. Wirganowicz PZ, Watts HG: Surgical risk for elective excision of benign exostoses. J Pediatr Orthop 17:455–459, 1997 43. Witthaut J, Steffens KJ, Koob E: Intermittent axillary nerve palsy caused by a humeral exostosis. J Hand Surg Br 19:422– 423, 1994 44. Woertler K, Lindner N, Gosheger G, Brinkschmidt C, Heindel W: Osteochondroma: MR imaging of tumor-related complications. Eur Radiol 10:832–840, 2000 45. Yamamoto T, Tanaka K, Nagira K, Marui T, Akisue T, Kurosaka M, et al: Intermittent radial nerve palsy caused by a humeral osteochondroma: a case report. J Shoulder Elbow Surg 11:92–94, 2002 46. Yoo JH, Min KD, Kim CK, Cha JG: A case of extension loss of great toe due to peroneal nerve compression by an osteochondroma of the proximal fibula. Arch Orthop Trauma Surg 130:1071–1075, 2010 47. Yu K, Meehan JP, Fritz A, Jamali AA: Osteochondroma of the femoral neck: a rare cause of sciatic nerve compression. Orthopedics 33:597, 2010 Manuscript submitted February 12, 2013. Accepted November 18, 2013. Please include this information when citing this paper: published online January 3, 2014; DOI: 10.3171/2013.11.JNS13310. Address correspondence to: Selçuk Göçmen, M.D., Department of Neurosurgery, Haydarpasa Training Hospital, Gulhane Mili tary Medical Academy, Kadikoy, Istanbul 36680, Turkey. email: [email protected].
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Peripheral nerve injuries due to osteochondromas: analysis of 20 cases and review of the literature Clinical article Selçuk Göçmen, M.D.,1 Ali Kıvanç Topuz, M.D.,1 Cem Atabey, M.D.,1 Hakan Şimşek, M.D.,1 Kenan Keklikçi, M.D., 2 and Osman Rodop, M.D. 2 Departments of 1Neurosurgery and 2Orthopedics, Gulhane Military Medical Academy, Haydarpasa Training Hospital, Istanbul, Turkey Object. Nerve compressions due to osteochondromas are extremely rare. The aim of this retrospective study was to investigate the mechanisms, diagnostic evaluations, and treatment of nerve lesions due to osteochondromas, and to review the literature. Methods. The authors retrospectively reviewed their clinic data archive from 1998 through 2008, and 20 patients who were operated on due to peripheral nerve injuries caused by osseous growth were enrolled in the study. Patients’ age, duration of symptoms, localizations, intraoperative findings, and modified British Medical Research Council (MRC) and electromyography data obtained from hospital records were evaluated. The literature on this topic available in PubMed was also reviewed. All 20 patients underwent surgery, which consisted of tumor excision performed by orthopedic surgeons and nerve decompression performed by neurosurgeons. Results. There were 17 men and 3 women included in the study, with a mean age of 21 years (range 18–25 years). Three patients had multiple hereditary exostoses, and 17 had a solitary exostosis. All of the patients underwent en bloc resection. The most common lesion site was the distal femur (45%). The peroneal and posterior tibial nerves were the structures that were affected the most frequently. The mean follow-up was 3.9 years (range 2–7 years). After the surgery, all patients (100%) experienced good sensory recovery (modified MRC Grade S4 or S5). Conclusions. To the authors’ knowledge, no large series have reported peripheral nerve compression due to exostoses. The authors have several recommendations as a result of their findings. First, all patients with peripheral nerve compression due to an osteochondroma should undergo surgery. Second, preoperative electromyographic examinations and radiographic evaluation, consisting of MRI and CT to provide optimal information about the lesion, are crucially important. Third, immediate treatment is mandatory to regain the best possible recovery. And fourth, performing nerve decompression first and en bloc resection of osteochondroma consecutively in a multidisciplinary fashion is strongly recommended to avoid peripheral nerve injury. (http://thejns.org/doi/abs/10.3171/2013.11.JNS13310)
O
Key Words • osteochondroma • exostoses • nerve compression • peripheral nerve • electromyography steochondroma,
also known as osteocartilaginous exostosis, is the most common of all benign bone tumors. There are 2 types of osteochondroma, solitary osteochondroma and multiple hereditary exostoses (MHE).18 In the MHE type, there is a strong familial incidence, and it is an autosomal dominant disorder with variable penetrance. Osteochondromas can arise in any bone that has undergone endochondral ossification, but they are more commonly associated with the metaphyseal regions of the lower femur, upper tibia, and upper humerus.15 Clinical symptoms can result from mechanical irritation or compression of adjacent structures (such as soft tissues, bone, internal organs, peripheral nerves, spinal cord, and blood vessels), fracture, and malignant trans-
formation.44 Nerves can be damaged by direct trauma, pressure injuries, fractures, ischemic neuropathies, spontaneous hematomas, cysts arising from the joint, entrapments, and neoplasms. Nerve compression syndromes are the neurological symptom complexes caused by the mechanical or dynamic compression of a segment of a single nerve at specific sites as it passes through a narrow fibroosseous tunnel or an opening in a fibrous or muscular structure.21 In the literature, only individual cases of peripheral nerve compression secondary to solitary osteochondromas are available.2,4–6,8–20,22–34,36–38,40–47 This case series is the largest series of peripheral nerve compressions due to solitary osteochondromas, and our aim in this retrospective study was to investigate the mechanisms, diagnostic
Abbreviations used in this paper: EMG = electromyography; MHE = multiple hereditary exostoses; MRC = Medical Research Council.
This article contains some figures that are displayed in color online but in black-and-white in the print edition.
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S. Göçmen et al. evaluations, and treatment of nerve lesions due to osteochondromas, and to review the literature.
Clinical Data Review
Methods
Twenty patients with osteochondroma were admitted to Gulhane Military Medical Academy (Haydarpasa Training Hospital Departments of Neurosurgery and Orthopedic Surgery) for management of exostoses between June 1998 and December 2008. Medical records and diagnostic imaging of these patients were obtained and reviewed (Table 1). Exostoses were classified as solitary or associated with a history of MHE. Medical records were evaluated for age, initial/chief complaint, duration of symptoms, and symptoms indicative of neural structure compression (peripheral nerve injuries). Physical examinations were reviewed for neurological deficits (modified British Medical Research Council [MRC] grade35), palpable mass, and other pertinent findings. Electrophysiological studies, plain radiography, CT, and MRI in the preoperative and postoperative periods were available in all patients. Method of treatment, surgical margins, histopathology, and complications were evaluated. Diagnosis was confirmed histopathologically. Follow-up evaluations were reviewed for progression or recurrence of symptoms, and tumor enlargement or recurrence. Literature Review
The literature was reviewed using the PubMed data-
base and bibliographies of published papers. Cases were reviewed for clinical details including age, symptoms, method of treatment, resolution of symptoms, and tumor recurrence. The nerve injury and site of origin on the bone of the exostoses were recorded. Surgical Data
In our patient series, the surgical indication was peripheral nerve compression due to a solitary osteochondroma. All patients underwent surgery for neurological involvement via a team-based approach, consisting of a neurosurgeon first exploring and preserving the nerve, followed by tumor resection by an orthopedic surgeon. Our experiences and intraoperative observations show that there are 2 main categories of peripheral nerve compression due to osteochondromas: a direct extrinsic pressure to the nerve, and growth of the osteochondroma causing circumferential ring formation that surrounds the peripheral nerve (Fig. 1). Direct extrinsic compression comprises 2 subtypes: integrity of the nerve preserved, and integrity of the nerve impaired (splitting the nerve). As another point of interest, the neurovascular structures were found to be adherent to the osteochondroma by a fibrous band. Therefore, we had to carefully dissect the fibrous band and release the neurovascular structures before the tumor was removed to avoid surgery-related severe neurovascular complications during tumor excision. After decompression surgery, it was observed during the follow-up period that patients recovered completely. Complete removal of the solitary exostoses provided a
TABLE 1: Characteristics of the 20 patients with peripheral nerve injuries due to osteochondromas Case No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
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Age (yrs), Type of Sex Osteochondroma 20, M 21, M 21, M 25, M 20, M 22, F 21, M 21, M 21, M 18, M 21, M 20, M 22, M 22, M 21, M 20, M 20, M 18, F 24, F 22, M
solitary solitary solitary solitary solitary solitary solitary solitary solitary MHE MHE solitary solitary solitary solitary solitary solitary MHE solitary solitary
Location of Exostoses
Nerve Injury/ Chief Complaint
Results
lt distal femur rt proximal humerus lt distal femur lt proximal femur lt proximal tibia rt clavicle rt fibula head lt proximal radius rt distal femur rt distal femur lt distal femur rt distal femur lt fibula head lt proximal humerus lt proximal humerus lt distal fibula rt fibula head lt distal femur lt distal femur lt distal femur
peroneal/posterior tibial radial peroneal/posterior tibial sciatic peroneal brachial plexus peroneal radial peroneal/posterior tibial peroneal/posterior tibial peroneal/posterior tibial peroneal/posterior tibial peroneal radial radial peroneal peroneal peroneal/posterior tibial peroneal/posterior tibial peroneal/posterior tibial
no symptoms 2 yrs no symptoms 5 yrs no symptoms 6 yrs no symptoms 2 yrs no symptoms 4 yrs no symptoms 5 yrs no symptoms 4 yrs no symptoms 5 yrs no symptoms 4 yrs recurrence at 3 yrs postop; no symptoms 4 yrs after 2nd op no symptoms 4 yrs no symptoms 4 yrs no symptoms 3 yrs no symptoms 4 yrs no symptoms 3 yrs no symptoms 5 yrs no symptoms 3 yrs no symptoms 2 yrs no symptoms 3 yrs no symptoms 3 yrs
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Nerve injuries due to osteochondromas In total, all patients (100%) improved to modified MRC Grade M4 or M5 motor function during the postoperative period. Several patients recovered motor function within hours or days following surgery. The majority of patients recovered in several months. The results of the sensory improvement were similar to that of motor dysfunctions. Nineteen of 20 patients had fair sensory functions (modified MRC Grade S2 or S3). Only 1 patient had no sensation (modified MRC Grade S0). After surgery, all patients (100%) had good sensory recovery (modified MRC Grade S4 or S5). Electromyography Data
Fig. 1. Anteroposterior plain radiographs (left column) and illustrations (right column) show the 2 main categories of peripheral nerve compression due to osteochondromas. A: Direct extrinsic pressure to the nerve (arrow). B: Growth of the osteochondroma causing circumferential ring formation that surrounds peripheral nerves (arrow). Copyright Selçuk Göçmen. Published with permission.
cure; however, 1 patient with MHE experienced tumor recurrence 3 years after resection.
Patient Characteristics
Results
Three female and 17 male patients were treated at our institution (Table 1). Three patients had MHE and 17 had a solitary exostosis. The mean age was 21 years (range 18–25 years). Patients with MHE were younger than patients with solitary exostoses, as the mean age for patients with MHE was 19 years (range 18–21 years) compared with 21.3 years (range 20–25 years) for patients with solitary exostosis. The mean follow-up duration was 3.9 years (range 2–7 years).
Sensorimotor Outcome
The sensorimotor recovery was scored on a scale ranging from 0 to 5 points, as recommended by the modified MRC. Preoperatively, all patients had weakness and sensory disturbances. Nineteen of 20 patients had fair motor functions (modified MRC Grade M2–M3; Table 2). Only 1 patient had total loss of motor function in the peroneal nerve–innervated musculature (modified MRC Grade M0). All of the patients (100%) who had motor dysfunction preoperatively were noted to experience improvement in their motor function following surgery (p < 0.01). Only 1 patient had no motor function preoperatively, but in the postoperative follow-up period he showed improvement in motor function to modified MRC Grade M4.
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The electromyography (EMG) studies were repeated after surgery for the patients with impaired EMG findings, consisting of slow conduction velocities and reduced motor and sensory nerve action potential in the preoperative periods. Sixteen of the 20 patients exhibited an incomplete axonal loss pattern, 3 had a mixed pattern, and 1 had a pure conduction block pattern. Electromyography performed after resection of the exostoses suggested nerve recovery and remyelination. In our series, the majority of the lesions were located in the distal femur (45%), followed by the fibula (20%), proximal humerus (15%), proximal tibia (5%), proximal femur (5%), clavicle (5%), and radius (5%; Table 3, Figs. 2–6). The peroneal and posterior tibial nerves were the most commonly affected nerve structures (Fig. 7). Patients with osteocartilaginous exostoses of the proximal humerus and radius had palsies of the radial nerves. The majority of the peripheral nerve injuries due to osteochondromas (50%) were located in the left lower extremities.
Patients With MHE
Two (66.7%) of 3 patients with MHE had a painful mass and weakness as the initial complaint. All patients with MHE had symptoms or findings on physical examination consistent with neural structure compression. All the lesions in these patients were modified MRC M3 levels before the operation (Table 2, Fig. 8). The motor scores of all the patients were M5 levels after the operation. One patient who experienced tumor recurrence 3 years after surgery reported pain at follow-up evaluation. This patient underwent repeat excision of the lesion by the orthopedic surgeons. There was no tumor recurrence after the second procedure during his 4-year follow-up. Two of 3 patients had no complications, no tumor recurrence, and had complete resolution of symptoms after a mean follow-up of 3 years (range 2–4 years).
Patients With Solitary Lesions
Eight (47.1%) of 17 patients with solitary lesions had a painful mass and weakness, whereas 6 (35.3%) had only a mass and weakness. Three (17.7%) of 17 patients had pain and weakness as their initial complaint. All patients with solitary lesions had symptoms or findings on physical examination consistent with neural structure compression. Nine (53%) of 17 patients had M3-level motor scores and 8 (47.1%) had M2-level motor scores before the operation. These patients were treated surgically with lesional resec1107
S. Göçmen et al. TABLE 2: Sensorimotor outcomes after surgery according to the modified MRC scale Motor Recovery Outcomes
M0
preop findings postop findings
1
M1
M2
M3
8
11
tion and nerve decompression. There were no complications, no tumor recurrence, and complete resolution of symptoms after a mean follow-up of 3.8 years (range 2–6 years). We observed good recovery (M5) in all of these patients (Table 2). Literature Review
The review of the literature revealed 41 cases of peripheral nerve compression secondary to solitary osteochondromas. The age of the patients in this review ranged from 3 to 69 years, and most patients were less than 25 years old (mean 23.7 years). Most patients were male (male to female ratio of 25:9). Multiple hereditary exostoses were positive in 12 patients (32.4%) in 37 documented cases. The proximal fibula was the most frequently attacked area in 59 patients (36.6%). The peroneal nerve had the largest entrapment rate (46.6%). The proximal humerus was the most frequently afflicted region in the upper extremities (50%); it was detected in 10 cases. Forty-nine of 54 patients who underwent surgery experienced good outcomes. The outcomes of the remaining 3 cases were poor and 2 cases were unknown. Gray et al. reported the first splitting of a nerve by an osteochondroma.12
Sensory Recovery M4
M5
9
11
S0 1
S1
S2
S3
9
10
S4
S5
10
10
consistent with neural structure compression. This study provides the largest clinical series of osteochondromas due to peripheral nerve compression from a single institution. Solitary osteochondromas have their highest incidence within the 2nd and 3rd decades of life, with a predominance of males affected.27 The ages and gender distributions of our patients with solitary lesions were consistent with those in the literature. Multiple osteochondromas occur as part of a rare familial syndrome with autosomal dominant inheritance (MHE).44 Three patients had MHE in our cases. Osteochondromas may be found in nearly every bone, with the exception of the calvaria.39 The most frequent sites of involvement include the knees, humerus, hips, scapula and ribs, wrists, ankles, elbows, hands, feet, and pelvis.39 Osteochondromas of the peripheral skeleton can cause nerve compression with consecutive entrapment neuropathies or nerve palsies. The peroneal nerve or radial nerve is the most frequently affected structure. Motor weakness or peroneal nerve palsy can occur as sequelae of chronic neural compression by osteochondromas lo-
Discussion
Osteochondroma, or osteocartilaginous exostosis, is a benign cartilage-forming lesion that comprises 10%–15% of all bone tumors.44 Osteochondromas are usually asymptomatic. However, several potential tumor-related complications can occur, especially in lesions with marked extent or location in critical anatomical sites.44 Skeletal complications including deformity, joint dysfunction, fracture, and malignant degeneration are the most common.38 Nonskeletal extrinsic complications due to mass effect on the adjacent tissues, including soft tissue, vascular, and neurological structures, are relatively rare. Nerve compression is extremely rare, present in less than 1% of all cases.8,24,38 However, the majority of the patients in our series and cases identified in the literature had presenting symptoms TABLE 3: Lesion localizations and nerve compressions Localization
Nerve Entrapment
Value (%)
distal femur fibula proximal humerus proximal tibia proximal femur clavicle radius
peroneal/posterior tibial peroneal radial peroneal sciatic brachial plexus radial
9 (45) 4 (20) 3 (15) 1 (5) 1 (5) 1 (5) 1 (5)
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Fig. 2. Case 5. A: Lateral plain radiograph shows a bone lesion (arrow) before surgery. B: Sagittal MR image shows a bone lesion attached to the proximal tibia by a pedicle (arrow). C: Photograph of excised bone lesion with its pedicle.
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Fig. 3. Case 6. A: An anteroposterior plain radiograph reveals an osteochondroma (arrow) of the right clavicle that was compressing the brachial plexus. B: Axial CT scan identifying the lesion (arrow). C and D: Coronal (C) and axial (D) MR images of the same patient showing the lesion (arrow).
cated at the proximal tibiofibular articulation.39,44 Palsies of the axillary and radial nerves have been described in patients with osteocartilaginous exostoses of the proximal humerus.39,44 In our series, the majority of the lesions were located in the distal femur (45%), followed by the fibula (20%), proximal humerus (15%), proximal tibia (5%), proximal femur (5%), clavicle (5%), and radius (5%). In our cases the peroneal and posterior tibial nerves were the most frequently afflicted peripheral nerves. Osteochondromas may impinge on adjacent soft-tissue structures such as tendons, muscles, nerves, and vascular structures. Neurological complications are due to direct impingement upon adjacent nerves by an osteochondroma.39 Therefore, nerve decompression is performed very carefully. Teamwork is important to plan and perform a complete removal of the exostosis. First, the nerve should be explored and preserved by a neurosurgeon, and then an orthopedist should resect the tumor. If the nerve is not first explored, the patient becomes susceptible to severe and irreversible nerve injury. In the second type of lesion (Fig. 1B), nerve injuries are more common. Not only histological examination, but also electrophysiological studies can provide the definitive diagnosis. However, our experiences and intraoperative observations show that there is not only a direct extrinsic pressure to the nerve, but also circumferential ringlike tumor tissue that surrounds the nerve, resulting from the growth of an osteochondroma. The shape and size of the exostosis is variable. Some are pedunculated with a globose, “mushroom,” or “cauliflower-like” summit, or (smaller exostoses) with a sharp “thornlike” or “coat-hanger” appearance.3 Others have a broad sessile implant. The pedunculated exostoses are usually directed toward the diaphysis. Rarely, the exostosis can reach large sizes, which per se do not prove malignancy.3 Plain radiography is a very practical tool to determine J Neurosurg / Volume 120 / May 2014
Fig. 4. Case 7. A and B: Anteroposterior (A) and lateral (B) plain radiographs show the tumor (arrows) that arose from the proximal fibula, which was found to be an osteochondroma. C: Axial CT scans of the same lesion (arrows).
Fig. 5. Case 14. A and B: Anteroposterior plain radiograph (A) and axial CT scan (B) reveal an osteochondroma of the proximal humerus that was compressing the radial nerve. C and D: Intraoperative image of the lesion (C) and the tumor that was removed surgically (D).
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Fig. 6. Case 17. A: Anteroposterior plain radiograph showing a proximal fibula osteochondroma. B and C: Sagittal (B) and axial (C) MR images of the lesion.
the number, location, and morphology of the exostoses, and to document complications such as cosmetic and osseous deformities and fracture.39 Osteochondromas are best visualized on CT rather than MRI, as the bony nature of the lesions is most clearly delineated.7 Magnetic resonance imaging is the examination method of choice for detecting complications such as bursa formation, vascular compromise, tendon or nerve compression, and malignant transformation.39 Magnetic resonance imaging is valuable for verifying peripheral compressive neuropathies caused by osteocartilaginous exostoses.44 Changes in signal intensity, size, or position of the involved peripheral nerve have been shown to represent suggestive MRI findings of compressive and entrapment neuropathies.44 On MR images, osteochondromas are observed as an isointense signal with a low-signal rim produced by the cortical bone.7 Preoperative MR images and CT scans should be examined carefully to provide optimal information about the lesion and aid treatment options. All the patients in this series underwent electrophysiological examinations. A needle electromyographic study usually reveals a pattern of abnormality consistent with a lesion. Surgical findings determine adhesion of the involved nerves. The final diagnosis has to be made using histopathological investigation.
The general surgical indications for benign bone growths are cosmetic defect, exostosis in a location at risk to repetitive trauma, increased risk of the exostoses to fracture, neurological involvement, impairment of the articular range of motion, and suspicion of malignancy.8 Total en bloc excision of the tumor is the treatment of choice.1 Other investigators have similarly reported a higher recurrence rate after curettage and bone grafting (41%) as opposed to resection (7%).1 After decompression surgery, all of our patients described above reported almost complete recovery neurologically, and electrophysiological tests were normalized thereafter. The surgeon must be cognizant that recurrence is common after incomplete removal of the lesion. Complete functional recovery is the goal, and delays in diagnosis and treatment can result in irreversible neurological impairments. Therefore, a teambased approach consisting of a neurosurgeon first exploring and preserving the nerve, followed by lesion resection by an orthopedic surgeon, offers the safest and optimal strategy. We believe that advanced axonal loss at the time of diagnosis was responsible for the unsatisfactory outcome, which emphasizes the importance of early diagnosis and treatment. Osteochondromas do not affect patient life expectancy. Malignant transformation is the most feared com-
Fig. 7. Case 13. A: Photograph of the operative plan. The lesion, caput fibula (CF), and incision lines are marked. B: The lesion was compressing the bifurcation of a peroneal nerve. The lesion was removed in 2 parts. A small piece of the lesion is noted in the photograph. The white arrow indicates the common peroneal nerve, the thick yellow arrow indicates the superficial peroneal nerve, the thin yellow arrow indicates the deep branch of the peroneal nerve, the red arrow shows the peroneus longus muscle, and the blue arrow shows a small piece of the lesion. C: Photograph of the resected tumor in 2 pieces.
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Nerve injuries due to osteochondromas include the following. Conception and design: Göçmen, Topuz, Atabey, Şimşek. Acquisition of data: Göçmen, Topuz. Analysis and interpretation of data: Göçmen. Drafting the article: Göçmen, Şim şek. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Göçmen. Administrative/technical/material support: Göçmen. Study supervision: Topuz, Atabey, Şimşek, Keklikçi, Rodop. References
Fig. 8. Case 10 with MHE. A: Anteroposterior plain radiograph shows bilateral osteochondromas of the distal femur (thin arrows) and left proximal tibia (wide arrow). B: Anteroposterior plain radiograph shows the proximal humerus with the osteochondroma (arrow). C and D: Axial (C) and coronal (D) MR images showing the lesion.
plication of osteochondroma. Osteochondromas may undergo sarcomatous transformation later in life, usually to a chondrosarcoma. Whereas the prevalence of complications in solitary osteochondromas has been estimated to be approximately 1%, this complication rate is higher with MHE, previously reported to be observed in as many as 25% of patients,39 although a lower prevalence of 3%–5% has been suggested.39 Malignant transformation was not observed in our series.
Conclusions
All patients with peripheral nerve compression due to an osteochondroma should undergo surgery. The nerve should always be decompressed and protected as a first step before the resection of the bone lesion. Preoperative radiographic evaluation should consist of MRI and CT to provide optimal information about the lesion and aid treatment options. Teamwork is crucial to plan and perform a complete removal of the exostoses. To avoid complications regarding further nerve injury and provide the optimal and safest strategy of management, we recommend a team-based approach consisting of a neurosurgeon first exploring and preserving the nerve, followed by lesion resection by an orthopedic surgeon. Disclosure The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. Author contributions to the study and manuscript preparation
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