Fibrodysplasia ossificans progressiva (FOP), the so called “stone man disease,” is termed the most catastrophic disease of ectopic bone formation in humans.1,2 The disease is characterized by grotesque heterotopic ossifications occurring both spontaneously and after minimal trauma leading to complete immobilization by a “second skeleton.”1,2 Medical management may markedly and irreversibly aggravate this disease.2,3 Hyperostosis boosts may be triggered by intramuscular or intraoral injections of local anesthetics.4–6 Growing interest in FOP and related disorders is stimulated by recent publications about the underlying pathophysiology.7–11
Anesthetic management in FOP is challenging. Because needle trauma regularly induces bone formation,4–6 FOP is regarded until now as a relative contraindication for regional anesthesia. Although subcutaneous injections have a low ossifying potential, bone formation regularly occurs after minimal trauma to muscles and connective tissues, such as ligaments, i.e., structures which are regularly affected by regional anesthesia techniques.
General anesthesia is often recommended in FOP. However, airway management may be complicated by severe cranial and cervical ankylosis12,13 requiring fiberoptic intubation.14–16 Fiberoptic intubation must be performed with utmost care because airway instrumentation may also result in ossification. In addition, patients with FOP frequently present with a restrictive lung function16 due to a rigid thorax. The impairment in lung function may increase the risk of postoperative pulmonary complications.14 Thus, fiberoptic intubation with general anesthesia also includes several disadvantages and risks in this specific patient population.
Because strict subcutaneous injections have a low bone-forming potential in FOP,4 superficial nerve blockades with local anesthetics17 may be a safe alternative to general anesthesia. We present a case of ultrasound-guided ankle-foot block in a patient with FOP scheduled for forefoot osteomyelitis surgery.
A 33-year-old woman (38-kg bodyweight) with advanced FOP presented with progressive osteomyelitis originating from the fifth digit of her right foot. Both feet were severely mutilated. Her right foot and ankle were additionally hyperalgesic, hyperthermic, and markedly edematous (Fig. 1). Repeated attempts to cure the osteomyelitis by oral and intravenous antibiotic therapy only limited the systemic inflammatory responses temporarily but failed to cure the focus. A surgical resection of the infected bone and tissue structures was planned.
Preoperative evaluation revealed a complete active and passive immobility of the temporomandibular joint and cervical spine. A reduction in thorax mobility by ossified costovertebral joints and intercostal musculature, as documented by radiograph and computed tomography imaging, contributed to a restrictive pulmonary disease. Her respiratory condition was complicated by recurrent recent episodes of pneumonia.
In view of the anticipated complexity in airway management, ventilation and weaning, avoidance of airway instrumentation appeared desirable. Although we were aware that locoregional anesthesia techniques are relatively contraindicated in FOP,18 we planned a modified ankle block to avoid general anesthesia. Because experience with regional anesthesia in these patients is limited, we performed a preoperative provocation test with bupivacaine the week before surgery. After informed consent, a subcutaneous depot of 5 mL bupivacaine 0.5% and a depot of 5 mL saline (as control) were injected into corresponding spots of the left and right dorsal forearm, respectively. The injections were performed strictly subcutaneously under ultrasound guidance (MicroMaxx with linear array probe HFL-38; 6–13 MHz, SonoSite, Bothell, WA) and pen marked for subsequent reevaluation. Ultrasound investigation of the two corresponding forearm sites before and after the subcutaneous injections and 1 week later revealed no signs of ossifying boosts. Therefore, we regarded subcutaneous injections of bupivacaine as a safe technique in our patient.
The extent of forefoot inflammation was unclear. Therefore, blockade of all five nerves at the ankle level was planned. The performance of this block was complicated by the inability to move the ankle and foot in a neutral position. Superficial anatomical landmarks such as palpable malleoli or arteries19 were absent because of the severe mutilations and the current inflammatory swelling (Fig. 1). Sonography, however, allowed us to identify the landmarks and selective injection of local anesthetics into the subcutaneous tissue (Fig. 2). During injection, needle contact to muscles, tendons, and bones was avoided. Under standard anesthetic monitoring plain bupivacaine 0.5% was injected into the tibial nerve site (∼5 mL) and the deep peroneal nerve site (∼5 mL) using a 25-mm needle (Terumo® Neolus, Leuven, Belgium). A strict subcutaneous field block was used to anesthetize the superficial peroneal, sural, and saphenous nerve (∼15 mL). One-half hour after completion of the block, the patient was transferred to the operating room and uneventfully underwent surgery. There was no need for additional sedative or analgesic drugs. The injection sites were reevaluated 1 week later with ultrasound, revealing no tissue inflammation, tissue necrosis or other signs of new ossification.
Anesthetic management in patients with stone man disease is complicated by several aspects. Because minimal trauma caused by needles may induce bone formation, regional anesthesia is often regarded as relatively contraindicated. Ectopic bone formation occurs locally after minimal trauma to skeletal muscles and connective tissues, such as ligaments and other structures frequently affected by regional anesthesia techniques.
Ultrasound guidance allowed us to identify the relevant anatomical landmarks19 in our patient in whom regular anatomy was obscured by osteomyelitis-induced swelling and the preexisting mutilation of the skeleton. In addition, ultrasound guidance allowed us to strictly limit the local anesthetic injections to the epifascial tissue layer, which is crucial in patients with FOP to prevent further episodes of bone formation.4,20–24
Although our approach is obviously restricted to regional anesthesia techniques not requiring needle penetration through muscle and connective tissue (i.e., ankle block), our case report demonstrates that in selected cases regional anesthesia techniques are feasible in patients with FOP and can be performed safely when using ultrasound guidance.
1. Kaplan FS, Glaser DL, Pignolo RJ, Shore EM. A new era for fibrodysplasia ossificans progressiva: a druggable target for the second skeleton. Expert Opin Biol Ther 2007;7:705–12
2. Kaplan FS, Le MM, Glaser DL, Pignolo RJ, Goldsby RE, Kitterman JA, Groppe J, Shore EM. Fibrodysplasia ossificans progressiva. Best Pract Res Clin Rheumatol 2008;22:191–205
3. Janoff HB, Zasloff MA, Kaplan FS. Submandibular swelling in patients with fibrodysplasia ossificans progressiva. Otolaryngol Head Neck Surg 1996;114:599–604
4. Lanchoney TF, Cohen RB, Rocke DM, Zasloff MA, Kaplan FS. Permanent heterotopic ossification at the injection site after diphtheria-tetanus-pertussis immunizations in children who have fibrodysplasia ossificans progressiva. J Pediatr 1995;126:762–4
5. Luchetti W, Cohen RB, Hahn GV, Rocke DM, Helpin M, Zasloff M, Kaplan FS. Severe restriction in jaw movement after routine injection of local anesthetic in patients who have fibrodysplasia ossificans progressiva. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996;81:21–5
6. Nussbaum BL, O’Hara I, Kaplan FS. Fibrodysplasia ossificans progressiva: report of a case with guidelines for pediatric dental and anesthetic management. ASDC J Dent Child 1996; 63:448–50
7. Shore EM, Xu M, Feldman GJ, Fenstermacher DA, Cho TJ, Choi IH, Connor JM, Delai P, Glaser DL, LeMerrer M, Morhart R, Rogers JG, Smith R, Triffitt JT, Urtizberea JA, Zasloff M, Brown MA, Kaplan FS. A recurrent mutation in the BMP type I receptor ACVR1 causes inherited and sporadic fibrodysplasia ossificans progressiva. Nat Genet 2006;38:525–7
8. Blaszczyk M, Majewski S, Brzezinska-Wcislo L, Jablonska S. Fibrodysplasia ossificans progressiva. Eur J Dermatol 2003; 13:234–7
9. Kaplan FS, Groppe J, Pignolo RJ, Shore EM. Morphogen receptor genes and metamorphogenes: skeleton keys to metamorphosis. Ann N Y Acad Sci 2007;1116:113–33
10. Feldman GJ, Billings PC, Patel RV, Caron RJ, Guenther C, Kingsley DM, Kaplan FS, Shore EM. Over-expression of BMP4 and BMP5 in a child with axial skeletal malformations and heterotopic ossification: a new syndrome. Am J Med Genet A 2007;143:699–706
11. Vanden Bossche L, Vanderstraeten G. Heterotopic ossification: a review. J Rehabil Med 2005;37:129–36
12. Herford AS, Boyne PJ. Ankylosis of the jaw in a patient with fibrodysplasia ossificans progressiva. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2003;96:680–4
13. Schaffer AA, Kaplan FS, Tracy MR, O’Brien ML, Dormans JP, Shore EM, Harland RM, Kusumi K. Developmental anomalies of the cervical spine in patients with fibrodysplasia ossificans progressiva are distinctly different from those in patients with Klippel-Feil syndrome: clues from the BMP signaling pathway. Spine 2005;30:1379–85
14. Meier R, Bolliger KP. Anesthesiological problems in patients with fibrodysplasia ossificans progressiva. Anaesthesist 1996;45:631–4
15. Nargozian C. The airway in patients with craniofacial abnormalities. Paediatr Anaesth 2004;14:53–9
16. Newton MC, Allen PW, Ryan DC. Fibrodysplasia ossificans progressiva. Br J Anaesth 1990;64:246–50
17. Wooden SR, Sextro PB. The ankle block. anatomical review and anesthetic technique. AANA J 1990;58:105–11
18. Singh A, Ayyalapu A, Keochekian A. Anesthetic management in fibrodysplasia ossificans progressiva (FOP): a case report. J Clin Anesth 2003;15:211–3
19. Schabort D, Boon JM, Becker PJ, Meiring JH. Easily identifiable bony landmarks as an aid in targeted regional ankle blockade. Clin Anat 2005;18:518–26
20. Shipton EA, Retief LW, Theron HD, de Bruin FA. Anaesthesia in myositis ossificans progressiva. A case report and clinical review. S Afr Med J 1985;67:26–8
21. Lininger TE, Brown EM, Brown M. General anesthesia and fibrodysplasia ossificans progressiva. Anesth Analg 1989;68:175–6
22. Stark WH, Krechel SW, Eggers GW Jr. Anesthesia in ‘stone man’: myositis ossificans progressiva. J Clin Anesth 1990;2:332–5
23. Tumolo M, Moscatelli A, Silvestri G. Anaesthetic management of a child with fibrodysplasia ossificans progressiva. Br J Anaesth 2006;97:701–3
24. Vashisht R, Prosser D. Anesthesia in a child with fibrodysplasia ossificans progressiva. Paediatr Anaesth 2006;16:684–8