Heterotopic calcification in abdominal wounds

Heterotopic

Calcification

Michael J. Reardon,

MD, Areti Tillou, MD, Dina R. Mody, MD, Patrick

BACKGROUND: Heterotopic bone formation in abdominal incisions is a recognized but uncommon sequela of abdominal surgery. The condition of heterotopic bone formation in the abdominal scar may not only cause physical and/or emotional discomfort for the patient but also mimic a retained foreign body or recurrence of a malignant condition. All cases of two surgeons representing a wide variety of general and thoracic surgery were reviewed, and three primary cases and one recurrent case of heterotopic bone formation in an abdominal wound were identified. These cases are compared with the cases available in the English literature to enhance the recognition, appropriate diagnosis, and treatment options available for the patient with this unusual condition. METHODS: All cases for two surgeons representing a variety of general and thoracic surgery were reviewed. Three patients with painful heterotopic calcification of an abdominal incision requiring excision were identified. One patient had undergone an upper midline laparotomy for pancreatitis and the other two had undergone median sternotomy for cardiac surgery. One of these patients developed a painful recurrence of upper linea alba calcification. All patients were male and ranged in age from 51 to 74 years. Primary heterotopic calcification of the upper linea alba occurred between 2 and 4 months for all patients. All cases were treated with excision and primary tissue closure. The case of recurrent calcification occurred 1V2months after primary closure, and was treated with re-excision and 1,200 centirads of postoperative radiotherapy to the incision area over 3 days, starting on postoperative day 1. The 2 cases of primary heterotopic calcification successfully treated with the initial excision have been followed for 2 and 6 years respectively without recurrence. The case of recurrent heterotopic calcification treated with re-excision and postoperative radiotherapy has been followed for 10 months without recurrence. Am J Surg. 1997;173: 145-147. 01997 by Excerpta Medica, Inc.

From the Department of Surgery (MJR, PRR), Residency Program (AT), Department of Pathology (DRM), Baylor College of Medicine, The Methodist Hospital, Houston, Texas. Requests for reprints should be addressed to Michael J. Reardon, MD, Associate Professor of Surgery, Baylor College of Medicine, 6550 Fannin, Suite 2435, Houston, Texas 77030. Manuscript submitted July 19, 1995 and accepted in revised form October 19, 1995.

0 1997 by Excerpta All rights reserved.

Medica,

Inc.

in Abdominal

Wounds

R. Reardon,

MD, Houston, Texas

M

yositis ossificans traumatica (MOT) is heterotopic bone formation after trauma or surgery and has been recognized for a long time. The occurrence of MOT after orthopedic surgery, especially hip replacement surgery, has generated much of the literature on this phenomenon, its etiology, and its treatment.‘-i Heterotopic bone formation in abdominal scars is a subset of MOT that has been infrequently reported in the literature. We report three cases of heterotopic calcification of the abdominal scar that were symptomatic and required surgical excision. One patient had recurrence after excision and successfully underwent re-excision and postoperative x-ray therapy of the wound without recurrence.

DISCUSSION Considering the large volume of surgery performed requiring an abdominal incision, the reported incidence of heterotopic calcification of an abdominal scar is extremely low. Although the incidence of asymptomatic calcification of abdominal scars may be higher than the reported incidence indicates, the occurrence in our practice is still a rare event. The first case was reported in 1901 by Askanazy,4 and current review of the English literature (Table) reveals only 79 primary cases and 3 recurrent cases, when our cases are included. All the cases in our literature review resulted from vertical, usually midline, abdominal incisions for abdominal procedures. We have added four cases, two of which were calcifications in the upper linea alba after median sternotomy for cardiac surgery, and one that recurred and required re-operation. Heterotopic ossification closely resembles bone formation histologically and radiologically. It differs from dystrophic calcification of soft tissues that show no osteoblastic activity or marrow elements. The causes of heterotopic ossification in an abdominal wound remain obscure. There are two prevailing theories for this type of calcification in an abdominal WOUnd.1>X6J3 According to the first theory, small particles from the periosteum or perichondrium of the xyphoid process or symphysis pubis are inoculated during surgery into the surgical wound and subsequently lead to the formation of bone.4 This theory is supported by the fact that almost all reported incidences of heterotopic hone formation are from vertical incisions in which the upper or lower extent of the incision was carried up against the xyphoid, the costal margin, or inferiorly against the symphysis pubis. In incisions with both the horizontal and vertical component, calcification always occurs in the vertical component. In our cases, the abdominal incision was carried up against the xyphoid process for exposure, or the sternum was divided as well as the upper linea alba for exposure for cardiac surgery. Liberation of bone or cartilaginous particles from the periosteum and perichondrium of the sternum may occur even if the xyphoid process is not resected during laparotomy. Even minor trauma to the xyphoid process or sym0002-9610/97/$17.00 PII SOOO2-9610(96)00415-l

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TABLE

Author

Date

Primary Case(s)

Classen Sanders Lehrman Watkins Tama Eidelman Marteinsson Wong Pearson Apostolidis Charless Reardon

1960 1955 1962 1964 1966 1973 1975 1975 1978 1981 1992 1995

10 6 4 3 2 6 23 4 4 6 8 3 79

TOTALS

Recurrent Case(s)

Treated Operatively

Male

Female

Ref

0 0 0 0 0 1 0 0 0 0 1 1

5 5 4 1 2 6 6 3 3 6 3 4

10 6 1 3 2 5 18 3 4 5 8 3

0 0 3 0 0 1 5 1 0 1 0 0

5 6 7 8 9 10 11 12 13 14 15 -

3

48

68

11

physis pubis with a midline abdominal incision may result in ossification of the wound. This theory does not sufficiently explain heterotopic ossification with no close anatomic relationship to osseous tissue and also fails to explain the infrequent occurrence of heterotopic bone formation in scars after operations on bones where large numbers of osseous particles are liberated during surgery. The second theory contends that heterotopic ossification is a result of immature pluripotent mesenchymal cells differentiating to osteoblast or chondroblast as a reaction to local injury, ultimately resulting in formation of bone. This process has been termed osteogenic induction to emphasize the acquisition of osteogenic capacities in cells not normally involved in bone formation. This induction should require a factor, or factors, to drive the process. Experimental evidence for a diffusible osteogenic inductor or inductors exists but has failed to chemically characterize it or define its mode of action.3 Although this is an interesting hypothesis for the origin of heterotopic bone in abdominal wounds, it fails to explain the occurrence in vertical incisions only. The clinical characteristics seen in the literature appear to be fairly consistent. Age does not appear to be a predisposing factor, and the subjects of the reports have ranged in age from 25 to 81 years, consistent with our patients. Most patients in the literature were operated on for a benign disease. As seen in Table 1, men dominate in this disease process with 68 out of 79 patients reported in the literature being male. Concurrently, all of our patients were men. Several explanations have been offered for this tendency, including the facts that the upper abdominal gastrointestinal surgeries often performed in the past were directed towards male-dominated diseases and that many of the surgeries performed on females in the past, such as hysterectomies, were often performed through transverse incisions that did not calcify. However, some authors feel that because men possess the ability to expand their thorax to a greater extent in anterior and posterior directions than do women, this might result in calcification initiated by greater tension to the wound during respiratory movements. Such tension might lead to cellular activity mediated through a piezoelectric effect.‘-’ In general, bone formation takes place within a few months and almost always within the first year after surgery. All of our patients had appear-

ante of the calcification within 2 months of the original procedure. Eidelman and Waron report a case of heterotopic bone formation within 27 days postoperatively.” Although it appears that in most of these patients the ossification occurred within 1 to 4 months, there is no limit to the exact time needed for osseous tissue to develop.” The size of heterotopic bone varies greatly in the literature, with the largest piece, reported by Pearson and Clark, being 15.5 x 4 cm.13 Our series included a piece 14.5 cm in greatest length. Of particular interest is the fact that all patients reported to date had a vertical abdominal scar. Most of these were vertical midline scars, although several were high paramedian scars. We add to the literature two patients with calcification of the upper midline extension of a median sternotomy performed for cardiac surgery with calcification of the wound. In reviewing the literature and noting our own clinical there appears to be no correlation between experience, wound complications, such as infection, keloid, or hyperplastic scars, and the formation of heterotopic calcification.15 There also appears to be no known endocrine, metabolic, or biochemical disorder present in our patients or those in the literature.15 C a 1cmm, alkaline phosphatase, and parathortnone levels measured in patients two and three in our series were normal. There also appears to be no correlation to the type of closure or to any specific suture material should be restricted to patients or technique. I5 Treatment with local complaints caused by the presence of heterotopic bone, and aysmptomatic patients should be excluded from treatment. Treatment should consist of complete excision with primary closure when possible. We do not recommend additional therapy for patients with primary heterotopic calcification; however, for those with recurrence, external radiotherapy of up to 1,000 to 2,000 rads as suggested by Eidelman and Waron can be used, as in our third patient. ‘@~~-‘s Recurrence of heterotopic bone in surgical scar has been reported only twice (Table) prior to the reporting of our third patient. Three methods have been proposed to decrease the formation of heterotopic bone. Non-steroidal anti-inflammatories (NSAIDs-both ibuprofen and indomethacin) have been used to help prevent heterotopic calcification from forming.19~z3 The effect is probably exerted by inhibited formation of prostaglandins and related sub-

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CALCIFICATION stances, which, through the inflammatory response, are known to trigger local bone remodeling following trauma and experimentally induced ectopic ossification of soft tissue. Indomethacin is known to inhibit the differentiation of mesenchymal cells into osteogenic cells, and thereby into osteoblasts and osteoclasts, reducing the formation and reabsorptive phases of bone remodeling. Radiotherapy is being used and is felt to exert its influence by arresting the initial step of osteoid formation by altering DNA transcription. Rapidly dividing immature cells are susceptible to inhibition by radiotherapy. Diphosphates (ethindronate disodium) have been used preand postoperatively to discourage heterotopic bone formation.4 Diphosphates bind calcium phosphate, preventing hydroxyapatite crystallization and, in turn, bone mineralization. Unfortunately, when diphosphates are withdrawn, heterotopic bone formation tends to recur, and the drug is expensive. Although all three methods may be used, we do not find their use necessary in a primary heterotopic calcification. The NSAIDs or radiotherapy may be considered for recurrent heterotopic calcification.

SUMMARY Three cases of heterotopic bone formation in abdominal scars are presented. Two are unique in that they represent heterotopic calcification in the abdominal portion of a median sternotomy incision, and one recurred. The literature on the subject is reviewed. Only symptomatic heterotopic ossifications need treatment and can be treated by excision and primary closure. Recurrence after primary excision is rare and can be treated with re-excision and NSAIDs or radiotherapy to the wound.

REFERENCES I. Cope R. Heterotopic ossification. South Med J. 1990;83:10581063. 2. Hinck SM. Heterotopic ossification: A review of symptoms and treatment. R&b Nurs. 1994;19:169-173. 3. Bassett CAL. Current concepts of bone formation. 1 Bone Joint Surg. 1962;44:1217-1244. 4. Askanazy, M. Quoted by Lubarsch 0. Zur kenntniss der knochenbildunger in lunge und pleura. Verhandl Deutsch Path Gesdsch. 1901;3:102.

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5. Classen KL, Wiederanders RE, Hcrringtcm JL. Heterotopic bone formation developing in abdominal scarb. Stirfiery. 1960;47:918923. 6. Sanders RL. Bone formation in upper abdominal scars. Ann Surg. 1955;141:621-626. 7. Lehrman A, Pratt JH, Parkhill EM. Heterotopic bone in laparotomy scars. Am J Surg. 1962;104:591-596. 8. Watkins GL. Bone formation in abdommal scars after xiphoidectomy. Arch Surg. 1964;89:73 l-734. 9. Tama L. Heterotoplc bone formation in abdominal surgical scars: A report of two cases in brothers..JAMA. 1966;197:151-153. 10. Eidelman A, Waron M. Heterotopic ossification in abdominal operation scars. Arch Surg. 1973;107:87-88. 11. Marteinsson BTH, Musgrove JE. Heterotopic hone formation in abdominal incisions. Am J Surg. 1975;130:23-25. 12. Wong J, Loewenthal J. Heterotopic hone formation in abdominal scars. Surg Gyn Obst. 1975;140:893-895. 13. Pearson J, Clark OH. Heterotopic calcification in abdominal wounds. Surg Gyn Obst. 1978;146:371-374. 14. Apostolidis NS. Legakis NC, Gregoriadis GC, et al. Heterotopic bone formanon in abdominal operation scars. Am J Surg. 1981;142:555-559. 15. Charles J, Hunt JA. Heterotopic hone formation in abdominal incisions. Hncvnii Med J. 1992;51;65-69. 16. An HS, Ebraheim N, Kim K, et al. Heterotopic ossification and pseudoarthrosis in the shoulder following encephalitis. A case report and review of the literature. Clin Orthol) Rel Res. 1987;219:291298. 17. Coventry MB, Scanlon PW. The
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