sacral_insufficiency_fracture

Since they were first described as a clinical entity in 1982 by Lourie 1), the awareness of this entity among healthcare professionals has increased.

SIFs occur in the sacral ala 2).

SIFs are a common cause of debilitating back pain in the elderly.

SIFs commonly affect elderly women with osteoporosis 3) 4).

Sacral insufficiency fractures (SIF) usually occur in elderly women and are secondary to various conditions, mainly postmenopausal or steroid-induced osteoporosis and radiation therapy.

Other reported risk factors include rheumatoid arthritis, multiple myeloma, Paget disease, renal osteodystrophy, and hyperparathyroidism 5) 6). 7) Of these, osteoporosis is the most prevalent, and almost all patients with SIFs will demonstrate severe osteopenia on dual x-ray absorptiometry, even if other risk factors are present 8).

Prior pelvic radiation is another well-established risk factor for the development of SIFs, with a reported prevalence of 21%–34%. 9).

99mTc-methylene diphosphonate (99mTc-MDP) bone scans in 80 patients, 30-80 years old (average, 62 years old) with uterine cancer who received high doses of radiation (10-60 Gy; average, 46 Gy) were reviewed retrospectively to evaluate the frequency of pelvic insufficiency fractures caused by radiotherapy and to study the appearance of the fractures on bone scans. Bone scans in 29 of 80 patients showed abnormalities in the pelvis: insufficiency fractures were identified in 27 patients (34%) and osseous metastases were found in two patients (3%). The fractures and metastases were diagnosed by CT and were confirmed by observing the patients' clinical courses. Fractures were identified in 27 (39%) of 69 postmenopausal women and in none of 11 premenopausal patients (p greater than .05). Fractures were found in 21 (84%) of 25 patients who had pelvic pain and in six (11%) of 55 patients who were asymptomatic (p greater than .001). Scintigrams in patients with fractures showed more than one fracture in most patients (85%), and fractures were often symmetric (67%). Scintigrams in two patients with osseous metastases showed increased activity in an iliac wing that was outside the radiation field. Our results suggest that a marked increase in insufficiency fractures occurs after radiation therapy, especially in postmenopausal patients. A symmetric area of increased uptake of radionuclide is a characteristic scintigraphic appearance of an insufficiency fracture 10).

The incidence may even be as high as 89%, as suggested by a prospective study of patients undergoing pelvic radiation for cervical cancer. Eighteen women (nine premenopausal and nine postmenopausal) with advanced cervical carcinoma were studied prospectively with MR imaging. The examinations totaled 216 and were scheduled before radiation therapy, three times during radiation therapy, and eight times after radiation therapy. T1-weighted and short inversion time inversion recovery images were obtained. The images were evaluated by two radiologists in consensus. The criterion for fracture was edema, indicated by an area of high signal intensity on short inversion time inversion recovery images and corresponding low signal intensity on T1-weighted images. CT scans (n = 61) and bone scans (n = 58) were used to confirm each diagnosis of fracture.

Sixteen (89%) of 18 patients (seven premenopausal and nine postmenopausal) showed findings compatible with insufficiency fractures. Thirteen patients had more than one lesion. The first fracture was detected between 3 and 12 months after the end of radiation therapy. During the study, the fractures associated with edema subsided without treatment in 41 (79%) of 52 lesions in 15 (94%) of 16 patients. Fractures were confirmed with additional imaging in all 16 patients (CT in 14 patients and bone scanning in nine patients).

Radiation-induced insufficiency fractures were frequently seen in premenopausal and postmenopausal women within 12 months after radiation therapy. Multiple fractures developed within 24 months. Twenty-one percent of the lesions healed during the observation period of 30 months 11).

There is often a delay in diagnosis because clinical symptoms are frequently vague and nonspecific and can mimic a variety of pathologic processes in a predominantly elderly population, including radiculopathy and metastatic disease.

Plain radiographs were unhelpful in the detection of sacral insufficiency fractures, but showed the pubic fractures in five patients. Diagnoses of insufficiency fractures were made on bone scintigraphic demonstration of the typical 'H' shaped sacral pattern, or the combination of the partial 'H' pattern together with public uptake. Computed tomography was useful for confirmation of insufficiency fractures in doubtful cases. Recognition of insufficiency fractures helps to avoid the pitfalls of misdiagnosing tumour recurrence or bony metastases 12).

Bone scintigraphy and MRi maging are the most sensitive studies to detect SIFs, though findings have been described in a wide variety of radiologic modalities.

They are often overlooked or confused clinically and radiographically with metastatic disease.

The standard of care for the treatment of SIFs has been conservative management, with variable courses of bed rest, rehabilitation, and analgesics prescribed.

Sacroplasty has emerged as an alternative therapy for the treatment of SIFs, with prospective studies and case reports suggesting that it is a safe and effective therapy 13).

see Sacroplasty

Tumor-associated sacral insufficiency fractures (SIF) present a significant clinical challenge. As survival increases for many malignancies, sacral fractures associated with metastases, sacral or extended pelvic radiation, and paraneoplastic osteoporosis are increasingly common and yet remain difficult to treat in the setting of the potentially significant morbidity of open sacral surgery.

Sacroplasty is a safe and effective option for the palliation of sacral fractures in the oncologic population 14).

see sacral fixation.

The characteristics of 493 cases of sacral fractures reported in the literature and those of 15 personal cases were studied.

Most of the fractures occurred in women over 60 years of age. No trauma was identified in two-thirds of the cases. Clinical expression was not specific (back pain, sciatica, pelvic pain). Standard x-ray showed a fracture of the obturator frame in 38.8% of the cases but no direct or indirect signs of sacral fracture were seen in more than two-thirds of the cases. Tc99m scintigraphy had excellent sensitivity; a characteristic hyperfixation pattern for ming an “H” was observed but only in 42.7% of the cases. Computed tomography had similar sensitivity and confirmed the diagnosis in doubtful cases. Treatment was usually bed rest until satisfactory pain relief. Of particular importance were neurological complications although they were exceptional. Several factors favoring sacral fracture were found, mainly osteoporosis and prior radiotherapy of the pelvis.

Clinicians should be aware of this type of fracture which still remains largely over-looked in geriatric care units 15).

2016

Four cases of missed SIFs that were subsequently identified and treated. One patient was treated as mechanical lower back ache, another patient underwent root block and two patients underwent surgery for lumbar canal stenosis. None experienced relief of their symptoms after these procedures. Retrospective analysis of X-ray and magnetic resonance imaging data revealed SIFs that were confirmed by computed tomography scans. All four patients were treated for underlying osteoporosis. Two patients who underwent surgery were treated conservatively and other two were treated by sacroplasty involving injection of cement into the fracture. Sacroplasty produced immediate pain relief and early mobilization compared to the conservative group. SIFs should always be considered in the differential diagnosis of an elderly patient presenting with low back symptoms. Sacroplasty can be considered for immediate pain relief and rapid mobilization 16)

1998

10 cases of sacral fractures diagnosed within the rheumatology department at Southend Hospital over the last 5 yr. All presented with sudden-onset low back pain. The majority were elderly, frail, with chronic inflammatory disease (six with rheumatoid arthritis, one with polymyalgia rheumatica, one with vasculitis) and had received steroids. Diagnosis was delayed by the inability of plain radiographs to show these fractures and was ultimately demonstrated by technetium scintigraphy/computed tomography scan. We feel that this diagnosis should be considered in elderly patients with rheumatoid arthritis or other risk factors for osteoporosis who present with low back pain and sacral tenderness. Further clues may be parasymphyseal tenderness (suggesting associated pubic ramus fracture), elevated alkaline phosphatase and plain radiograph showing pubic ramus fractures or parasymphyseal sclerosis. Patients with this complication generally have a poor prognosis and two of our patients have died. Seven required in-patient stay (mean 20 days; range 14-41). The mortality, morbidity and costs incurred in management may be comparable to those of femoral neck fractures 17).

1995

22 Chinese patients with sacral insufficiency fractures were reviewed. Twenty-one were postmenopausal women. Other risk factors were external pelvic radiotherapy (eight) and total hip replacement (two). Severe low back pain was the most common presenting complaint. Fractures initially were demonstrated by bone scintigraphy in 21 and computed tomography (CT) in seven patients. Concomitant parasymphyseal and pubic rami fractures were detected in 17 and 10 patients, respectively. Follow-up assessment by CT and bone scintigraphy in five patients showed various stages of fracture healing. Recognition of the radiological patterns of this entity is emphasized 18).

1994

20 cases in a five-year period. Bone scans were positive in all 20 patients, CT showed a fracture or sclerosis in 7 of 12 patients and was useful in excluding malignancy. Plain radiographs were the least helpful, showing sclerosis in only 4 of the 20 patients. Involutional osteoporosis with a reduced bone formation rate was the most common underlying cause. Seventeen patients had complete resolution of pain within nine months, and no patient lost independence in daily activities. Increased awareness of these fractures may help to avoid unnecessary investigation and treatment. Bedrest and analgesia followed by rehabilitation provide good relief of symptoms 19).

1985

Distinctive vertical insufficiency fractures of the pelvis were found in nine osteopenic patients. Each patient had subacute pelvic pain without antecedent trauma. The sacral fractures healed fairly quickly, but the pubic fractures often had a protracted course. Eight patients had combined sacral and pubic fractures; one had only sacral alar fractures. In three patients the sacral fractures preceded the pubic fractures by 3-4 months. All nine patients had skeletal demineralization due to metabolic bone disease, radiation therapy, or multiple myeloma. Recognition of the association between pubic and sacral insufficiency fractures should aid in recognizing the diffuse nature of the skeletal disease so that unnecessary biopsy of the fracture sites can be avoided 20).

1982

Three elderly patients with incapacitating back and leg pain were found to have spontaneous osteoporotic fractures of the sacrum. The clinical picture in these three patients suggests a distinct clinical entity of spontaneous osteoporotic fracture of the sacrum (SOFS). This is characterized by severe low back, hip, and leg pain that suggests initially lumbosacral radicular compression, either from disk disease, spinal stenosis, tumor. However, objective mechanical signs more typical of those entities may be absent or minimal in SOFS. Symptoms suggestive of a cauda equina syndrome may be present, but there is minimal or no neurological deficit on examination. Marked sacral tenderness is a hallmark of SOFS 21).

A case of a 72-year-old woman who presented with severe low-back pain. She was thoroughly investigated for the cause of her back pain. Plain X-rays did not reveal any abnormality, but magnetic resonance (MR) scan revealed marked oedema within both sides of the sacrum, suggesting a neoplastic lesion. Bone scintigraphy did show a hyperfixation pattern forming an 'H' in the sacrum which is a characteristic sign of SIF. Computed tomography (CT) confirmed sclerotic changes interpreted as insufficiency fractures through both sacral alae. Increased awareness of these fractures may help to avoid unnecessary investigations and treatment. Bed rest and analgesia followed by rehabilitation provide good relief of symptoms 22).


1) , 21)
Lourie H. Spontaneous osteoporotic fracture of the sacrum. An unrecognized syndrome of the elderly. JAMA. 1982 Aug 13;248(6):715-7. PubMed PMID: 7097924.
2) , 3) , 6) , 20)
De Smet AA, Neff JR. Pubic and sacral insufficiency fractures: clinical course and radiologic findings. AJR Am J Roentgenol. 1985 Sep;145(3):601-6. PubMed PMID: 3875262.
4) , 22)
Wild A, Jaeger M, Haak H, Mehdian SH. Sacral insufficiency fracture, an unsuspected cause of low-back pain in elderly women. Arch Orthop Trauma Surg. 2002 Feb;122(1):58-60. PubMed PMID: 11995886.
5) , 8) , 19)
Gotis-Graham I, McGuigan L, Diamond T, Portek I, Quinn R, Sturgess A, Tulloch R. Sacral insufficiency fractures in the elderly. J Bone Joint Surg Br. 1994 Nov;76(6):882-6. Review. PubMed PMID: 7983111.
7)
Dasgupta B, Shah N, Brown H, Gordon TE, Tanqueray AB, Mellor JA. Sacral insufficiency fractures: an unsuspected cause of low back pain. Br J Rheumatol. 1998 Jul;37(7):789-93. PubMed PMID: 9714359.
9) , 12)
Peh WC, Khong PL, Sham JS, Ho WY, Yeung HW. Sacral and pubic insufficiency fractures after irradiation of gynaecological malignancies. Clin Oncol (R Coll Radiol). 1995;7(2):117-22. PubMed PMID: 7619761.
10)
Abe H, Nakamura M, Takahashi S, Maruoka S, Ogawa Y, Sakamoto K. Radiation-induced insufficiency fractures of the pelvis: evaluation with 99mTc-methylene diphosphonate scintigraphy. AJR Am J Roentgenol. 1992 Mar;158(3):599-602. PubMed PMID: 1739002.
11)
Blomlie V, Rofstad EK, Talle K, Sundfør K, Winderen M, Lien HH. Incidence of radiation-induced insufficiency fractures of the female pelvis: evaluation with MR imaging. AJR Am J Roentgenol. 1996 Nov;167(5):1205-10. PubMed PMID: 8911181.
13)
Lyders EM, Whitlow CT, Baker MD, Morris PP. Imaging and treatment of sacral insufficiency fractures. AJNR Am J Neuroradiol. 2010 Feb;31(2):201-10. doi: 10.3174/ajnr.A1666. Epub 2009 Sep 17. Review. PubMed PMID: 19762463.
14)
Moussazadeh N, Laufer I, Werner T, Krol G, Boland P, Bilsky MH, Lis E. Sacroplasty for cancer-associated insufficiency fractures. Neurosurgery. 2015 Apr;76(4):446-50. doi: 10.1227/NEU.0000000000000658. PubMed PMID: 25635890.
15)
Finiels H, Finiels PJ, Jacquot JM, Strubel D. [Fractures of the sacrum caused by bone insufficiency. Meta-analysis of 508 cases]. Presse Med. 1997 Nov 1;26(33):1568-73. French. PubMed PMID: 9452753.
16)
Sudhir G, K L K, Acharya S, Chahal R. Sacral Insufficiency Fractures Mimicking Lumbar Spine Pathology. Asian Spine J. 2016 Jun;10(3):558-64. doi: 10.4184/asj.2016.10.3.558. Epub 2016 Jun 16. PubMed PMID: 27340538; PubMed Central PMCID: PMC4917777.
17)
Dasgupta B, Shah N, Brown H, Gordon TE, Tanqueray AB, Mellor JA. Sacral insufficiency fractures: an unsuspected cause of low back pain. Br J Rheumatol. 1998 Jul;37(7):789-93. PubMed PMID: 9714359.
18)
Peh WC, Khong PL, Ho WY, Yeung HW, Luk KD. Sacral insufficiency fractures. Spectrum of radiological features. Clin Imaging. 1995 Apr-Jun;19(2):92-101. PubMed PMID: 7773883.
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