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Abstract. – OBJECTIVE: This is an exemplarycase report underlining a relevant morbidity whichcould be associated to the use of autologous iliaccrest bone graft (ICBG) for spine fusion.

CASE REPORT: Starting from 1990, a 25-years-old woman underwent two subsequent surgicaltreatments for non-Hodgkin lymphoma vertebrallocalizations. In the second surgery, arthrodesiswas obtained with autograft through right poste-rior iliac crest osteotomy. During the chemother-apy treatment following the surgery, the patientsuffered from infection at posterior iliac crestscar, the site of previous graft, caused by methi-cillin-resistant Staphylococcus aureus. She wassubjected to surgical debridement and specificantibiotic treatment with local healing and phlo-gosis index reduction. Chemotherapy protocolwas concluded and the patient healed with de-finitive lymphoma remission. After 22 years thepatient had a relapse of donor site infection, re-quiring a new antibiotic therapy and a new sur-gical debridement.

RESULTS: The relapsed infection at donor sitelasted for a long period, more than one year, de-spite of specific care. It finally healed after an-other accurate surgical debridement and post-operative antibiotic therapy.

CONCLUSIONS: This case report underlinesthe possible consequences on the patient’squality of life of a long-term disease affectingthe iliac crest bone graft donor site. Literatureconcerning alternatives to autograft for spine fu-sion is also reviewed.

Key Words:Spine fusion, Iliac crest bone graft, Bone substi-

tutes, Donor site, Morbidity.

Introduction

Iliac crest bone autograft (ICBG) has longbeen considered the gold standard for fusion pro-cedures in spine surgery. However, there are rec-

Iliac crest bone graft: a 23-years hystory ofinfection at donor site in vertebral arthrodesisand a review of current bone substitutesL. BABBI, G. BARBANTI-BRODANO, A. GASBARRINI, S. BORIANI

Department of Oncological and Degenerative Spine Surgery, Istituto Ortopedico Rizzoli, Bologna,Italy

Corresponding Author: Lisa Babbi, MD; e-mail: lisababbi@yahoo.it.

ognized drawbacks on iliac crest bone graft, in-cluding increased operative time, increased bloodloss, increased donor site morbidity, and a limita-tion to the amount that can be realistically har-vested for multilevel fusion1. Successful fusionhas been demonstrated following iliac crest bonegrafting in various applications in lumbar spinesurgery2,3. However, the morbidity rates associat-ed with the use of ICBG remain high, with somestudies reporting up to a 50% rate of persistentdonor site pain, paresthesias, hematoma and in-fection4. Other authors5-8 describe a complicationrate ranging from 2.4% to 5.8% for major com-plications and from 9% to 37.9% for minor com-plications. Because of donor site morbidity, spinesurgeons have increasingly used synthetic and re-combinant bone graft extenders, and a whole in-dustry has arisen from this market9: local auto-graft, allograft, demineralized bone matrix(DBM), synthetic bone grafts (ceramics), bonemorphogenetic proteins (BMPs), autogenousgrowth factors (AGFs), bone marrow aspirate(BMA) and collagen-based matrices are the mostpopular bone graft substitutes gaining popularityand being increasingly used in the lumbar spine.We report here a peculiar case of a 25 yearsICBG site infection in a patient submitted to re-vision surgery because of a T10 non-Hodgkinlymphoma: the intention of this exemplary casereport is to remind how the morbidity in auto-graft shouldn’t be underestimated and it also rep-resents an occasion to review the synthetic alter-natives and report our experience in this field.

Case ReportA 49-years-old woman presented at admission

with worsening pain at right pelvis and recurrentfever. Twenty-two years before, she underwent asurgical debridement for an infection due to Me-thicillin-Resistant Staphylococcus aureus (MR-

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SA) occurring at iliac crest in the site of a previ-ous bone autograft. Microbiological results fromneedle biopsy confirmed an active MRSA localinfection at posterior iliac crest where a fistulaappeared. The patient’s history was collected: in July

1990 the patient (aged 25-years-old) was referredto our unit because of a T10 neoformation com-pressing the epidural space and submitted to T10posterior decompression and secondary T9-T11stabilization with Hartshill hardware. Twentymonths later a T8 wedge fracture occurred andthe patient was urgently admitted to our unit andunderwent hardware removal and new arthrode-sis with T6-T12 Roy-Camille plates. Arthrodesiswas obtained with autograft through right poste-rior iliac crest osteotomy. The histological examrevealed a high-grade non-Hodgkin lymphomaand patient was addressed to the Onco-Hemato-logic Unit. Two months after discharge the pa-tient began chemotherapy according to the F-MACHOP protocol consisting of 6 cycles, butsoon after the first cycle a fistula appeared in thewound scar at the right iliac crest, the site of theprevious graft. Phlogosis blood index increased.Subsequent hospitalization was necessary andmicrobiological diagnosis of methicillin-resistantStaphylococcus aureus (MRSA) infection at pos-terior iliac crest scar was made after swab. A sur-gical debridement of the abscess was performed,washing drains were left in place for few daysand a treatment with specific antibiotic was per-formed for other 8 days with local healing andphlogosis index reduction.Chemotherapy protocol was concluded and the

patient healed with definitive lymphoma remis-sion. The patient underwent regular clinical andradiological follow-up; she stayed asymptomatic,both at lumbar and iliac crest sites, for severalyears until Summer 2014 when symptoms andlocal signs of donor site infection relapsed.At this time an antibiotic specific therapy with

Daptomycin, Oxacillin and Linezolid started, anda new surgical debridement was performed.Despite the specific care, the infection was

still present in Autumn 2015, after 23 years fromthe graft, when the patient came back to our at-tention. At admission, she presented painful atthe right side with a purulent fistula at the donorsite (Figure 1).Surgical debridement was performed (Figure

2) with wide curettage of the pathological areaand copious washings. A postoperative specificantibiotic therapy started and continued until

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Figure 1. Preoperative CT images of iliac donor site infec-tion 23 years after grafting. A central large osteolysis is sur-rounded by sclerotic bone.

blood phlogosis index negativity. Currently, thebody scan is negative, the wound healed and thepatient is asymptomatic.

Discussion

In order to achieve fusion in vertebral surgicalprocedures, the instrumentation can stabilize thespine at first and then the final success dependson both biological and host factors, which deter-mine fusion to the adjacent bone segment. Manyspinal fusion procedures require the use of bonegrafts, and spinal fusion largely depends on theosteoconductive and osteoinductive properties ofbone grafts or their substitutes.The massive amount of cancellous bone that

can be obtained from the inner table of the pelvisprovides all the desired properties of osteocon-duction, osteoinduction and osteogenicity, neces-sary to obtain a solid arthrodesis. The large sur-face area of this bone graft has the optimal chem-istry, structure, and porosity to serve as an excel-lent scaffold for new bone formation. Similarly,it contains all the necessary bone-forming growthfactors and it is inherently osteoinductive. Fur-

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L. Babbi, G. Barbanti-Brodano, A. Gasbarrini, S. Boriani

Figure 2. Preoperative MRI (A, B) shows liquid at iliac crest contest hyperintense in T2 and hypointense in T1, compatiblewith purulent material. PET scan (C) confirms contrast enhancement at iliac right site. D, Preoperative cutaneous fistula.

rates ranging from 4 to 49%. These complica-tions included superficial infection, minor woundproblems, temporary sensory loss, and mild ortransient pain. Swan and Goodacre17 studied thecomplications of iliac bone harvesting in 72 pa-tients. The postoperative donor site complica-tions included persistent pain at the donor site in7% of cases (all resolved within 6 months) andsuperficial wound infections in 3% of cases (suc-cessfully treated with oral antibiotics). In all ofthe studies reviewed, there were no reports oflong-term infective complications at the iliaccrest donor site. In the literature there are others example of

wound/donor site infection after ICBG proce-dures: Calori et al18 found local infections at thedonor site in 14.28% cases of ICBG group; ac-cording to Pirris et al9, one patient (4%) of his se-ries developed a deep wound infection that re-quired operative irrigation and debridement. Ar-maghani et al19 report one superficial wound in-fection and a postoperative hematoma, both ofwhich were treated successfully with close obser-

thermore, cancellous bone is easily re-vascular-ized and rapidly incorporated at the host site.There are no concerns for disease transmissionand no risks of immunogenicity10. The use of ili-ac crest bone graft (ICBG) has been well-sup-ported in the literature2,3,11,12 with fusion rates ashigh as 93%. Nowadays, it is considered the goldstandard in spine fusion. Morbidity associated with its use is also well

reported. Donor site morbidity can be attributedto the harvesting procedure of the ICBG. Thisprocedure is associated with longer operativetimes, increased estimated blood loss, and alonger hospital stay13,14. Major complicationshave been reported ranging from 0.7% to 25%,including infection, prolonged wound drainage,large hematomas, reoperation, pain lasting morethan 6 months, sensory loss, scar, joint subluxa-tion, gait disturbances, sacroiliac joint destabi-lization, herniation of abdominal muscles andcontents, iliac or pelvis fracture, and heterotopicbone formation15,16. Minor complications aremore common, with a reported complications

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vation and oral antibiotics; they register no deepwound infections requiring a revision surgery ora readmission to the hospital. Similarly to our case report, De Riu et al20 re-

port an unusual complication: a huge iliac ab-scess that appeared 4 years after bimaxillarysurgery involving iliac bone grafts. Concerningour case report, at our knowledge 25 years de-layed abscess has never been described before asa complication in ICBG donor site morbidity.For these reasons, much progress has been

made in the field of bone graft alternatives forspinal fusion; approximately 1,400 products areavailable on the international market for use asbone void fillers. We briefly review the mainICBG alternatives.Local autograft: Park et al21 have shown

equivalent fusion results for local laminectomybone autograft (ALB) and ICBG in a single levelposterolateral fusion.Allograft bone has been the most widely used

as a substitute to avoid complications of donorsite morbidity, but its use is associated with anincreased risk of infection and rejection, and ithas poor osteoinductive properties22. The report-ed fusion rates with the use of fresh-frozen or

freeze-dried allograft bone in posterolateral lum-bar fusions have wide variability in the litera-ture23, probably due to its poor osteogenic or os-teoinductive properties that do not induce newbone formation in the same manner as the auto-genous bone graft. Moreover, they generally pro-vide no initial mechanical support and must beused in conjunction with a scaffold or fixa-tion24,25.Ceramics are osteoconductive and biodegrad-

able bone graft scaffolds26-30. These agents con-sist of coralline hydroxyapatite, β-tricalciumphosphate, silicate-substituted calcium phos-phate, calcium sulfate, or a combination of theseminerals. Ceramics have several advantages;they are nontoxic, nonimmunogenic, easy to ster-ilize, and have limitless availability. Their disad-vantages are that they are brittle and have a littleshear strength or fracture resistance. Becausethey offer minimal mechanical stability in theimmediate postoperative period, ceramics areusually insufficient as scaffolds in lumbar fusionsurgery22,30. Platelet gels are osteoinductive and are used as

bone graft enhancers in conjunction with ICBG,ALB, or allograft bone. It would make logical

Figure 3. A, Intraoperative debridement with iliac crest bone milling. B, C, Postoperative CT showing bone defect afterdonor site debridement.

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sense that the addition of platelet gel to autolo-gous iliac crest would enhance fusion rates dueto the presence of TGF-β and PGDF. However,clinical study findings refute this hypothesis. Po-tential reasons for these results include rapid dis-solving of the platelet gel and diffusion ofgrowth factors29.With reported fusion rates of 95% to 98%,

bone morphogenetic proteins have revolutionizedthe ability to achieve successful fusion in thelumbar spine. BMP induces bone formation byinfluencing mesenchymal stem cells. Disadvan-tages include ectopic bone formation in the neur-al foramen and the central canal after BMP use;radiculitis, occurring just days after surgery, is al-so a known complication of BMP use, osteolysisalso a serious complication following BMP use.Wound dehiscence and infection have been re-ported in multiple papers31.Bone marrow aspirate (BMA) is both osteoin-

ductive and osteogenic. It is typically used with astructural graft to give it mechanical strength. Itsinherent advantages are the minimal harvestingsite morbidity and the high amount of Demineral-ized Bone Matrix (DBM) which has emerged toenhance, and often supplant, the use of freeze-dried allograft. DBM retains the same propertiesas freeze-dried allograft but without the mineralcontent. It serves as an effective osteoconductivescaffold and contains type I collagen and non-col-lagenous proteins. Much like allograft it is rela-tively inexpensive and unlimited in quantity com-pared to ICBG. Its main disadvantage is the in-herently variable osteoinductive properties. Theosteoinductivity of DBMs has been well docu-mented in preclinical studies32-34. However, fewclinical studies have evaluated the efficacy ofDBM as a bone graft extender in instrumentedposterolateral fusion with respect to an iliac crestbone autograft alone35,36. Our experience consistson an in vivo study aimed to carry out an evalua-tion of the osteoinductive and osteoconductiveproperties of two bone substitutes composed ofMgHA granules or HDBM-MgHA dispersed in abiomimetic matrix, which has previously shownin vitro37,38 biocompatibility and biological propri-eties similar to an autograft. The osteogenic abili-ty of these compounds was evaluated and com-pared with a cortical-cancellous bone autograft inan ovine model of lumbar spine instrumented fu-sion to reproduce a model as close as possible tothe surgical procedure performed on humans. Ourhistomorphometric results showed that MgHAstimulated the deposition of newly formed bone

tissue similar to autologous bone in a higheramount with respect to HDBM-MgHA. Finally,the bone surface to volume ratio parameter, a use-ful basic 3-dimensional parameter in characteriz-ing the complexity of structures, showed thatnewly formed trabecular bone around MgHA bio-material presented a greater surface than autolo-gous bone39. The Authors considered the combi-nation of osteoinductive and osteoconductive ma-terials such as DBM and concluded it can be avalid alternative to the autologous/homologousbone, thus perhaps overcoming the limitation ofcurrent therapeutic strategies.

Conclusions

Major and minor complications at donor siteare described in the literature. An ideal bonegraft substitute with little or no associated com-plications and risks does not exist at this time.Currently, autograft is considered to be the goldstandard but it shows few limitations: this casereport describes a 25-years disabling ICBGdonor site morbidity that required revision surg-eries during years. The recent development ofbone graft substitutes represents a great advancein caring for these patients. Each graft alternativehas advantages and disadvantages, and the op-tions must be considered on an individual, risk-benefit basis to select the best option for each pa-tient undergoing spinal fusion. This case reportalso underlines the possible consequences on thequality of life in patients with rare, but still possi-ble, chronic long-term donor site disease.

––––––––––––––––––––AcknowledgementsThe Authors thank Mr. Carlo Piovani for his helpful collab-oration in patients’ images storage and editing and Dr. Cris-tiana Griffoni for support in the manuscript editing.

–––––––––––––––––-––––Conflict of InterestThe Authors declare that there are no conflicts of interest.

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