Dislodgement and gastrointestinal tract penetration of bone cement used for spinal reconstruction after lumbosacral vertebral tumor excision: A case report.

INTRODUCTION: Polymethylmethacrylate (PMMA) cement is useful for spinal reconstruction, but can cause complications including new vertebral fractures, neurological disorders and pulmonary embolism. We report a case in PMMA cement used for spinal reconstruction after tumor curettage dislodged and penetrated the gastrointestinal tract. DIAGNOSES: The patient was diagnosed with a retroperitoneal extragonadal germ cell tumor at age 27 years. After chemotherapy and tumor resection, the tumor remained. It gradually increased in size and infiltrated lumbosacral vertebrae, causing him to present at age 35 years with increased low back pain. Image findings showed bone destruction in the vertebral bodies accompanied by neoplastic lesions. The left and right common iliac arteries and inferior vena cava were enclosed in the tumor on the anterior side of the vertebral bodies. Lumbosacral bone tumor due to direct extragonadal germ cell tumor infiltration was diagnosed. A 2-step operation was planned; first, fixation of the posterior side of the vertebral bodies, followed by tumor resection using an anterior transperitoneal approach, and spinal reconstruction using PMMA cement. After surgery, the PMMA cement gradually dislodged towards the anterior side and, 2 years 9 months after surgery, it had penetrated the retroperitoneum. The patient subsequently developed nausea and abdominal pain and was readmitted to hospital. The diagnosis was intestinal blockage with dislodged PMMA cement, and an operation was performed to remove the cement present in the small intestine. There was strong intra-abdominal adhesion, the peritoneum between the vertebral bodies and intestine could not be identified, and no additional treatment for vertebral body defects could be performed. After surgery, gastrointestinal symptoms resolved.
CONCLUSION: Although this was a rare case, when using bone cement for vertebral body reconstruction, the way of anchoring for the cement must be thoroughly planned to assure no cement dislodgement can occur.

Introduction

The usefulness of polymethylmethacrylate (PMMA) cement for vertebral body reconstruction after resection of a vertebral body tumor or for vertebroplasty to treat vertebral body tumors or osteoporotic vertebral body fractures has been reported.[ There have also been many reports of complications occurring when PMMA cement is used.[ The aim of this report is to describe a case of PMMA cement dislodged from vertebral bodies after tumor resection and vertebral reconstruction using PMMA cement followed by penetration of the cement into the gastrointestinal tract causing blockage.

Method

This is a case report, and informed consent was obtained from the patient and his wife.

Case report

Case

35-year-old male.

Chief complaint

Low back pain.

Past medical history

Nothing of note.

Family history

Nothing of note.

Current medical history

At the age of 27 years, he was diagnosed with a retroperitoneal tumor (extragonadal germ cell tumor). After chemotherapy, the tumor was resected, but strong adhesion between the tumor and surrounding tissue made it impossible to resect the entire tumor. The remaining tumor gradually increased in size and infiltrated lumbosacral vertebrae. Chemotherapy and radiotherapy were given to treat the remaining tumor, but low back pain gradually increased and the patient visited our department at the age of 35 years.

Physical findings and neurological findings

Other than strong low back pain, no neurological abnormalities were observed.

Blood biochemistry findings

At the time of his first examination at our hospital, alpha-fetoprotein (AFP) was 205.7 ng/mL and lactate dehydrogenase (LDH) was a high 1495 U/L, but human chorionic gonadotropin was normal at 0.4 mIU/mL. After undergoing chemotherapy and radiotherapy, AFP, LDH, and human chorionic gonadotropin values were all normal. The C-reactive protein value was 0.3 mg/dL, erythrocyte sedimentation rate was 3.00 mm/h and no inflammatory reaction was observed.

Image findings

Plain radiographs (Fig. 1) and computed tomography images (Fig. 2) showed bone destruction from L5 to S1. Magnetic resonance imaging with T1 weighted images showed iso signal intensity, T2 weighted images showed speckling with high intensity, and neoplastic lesions were observed with gadolinium contrast imaging. The left and right common iliac arteries and inferior vena cava were enclosed in the tumor on the anterior side of the vertebral bodies. The infiltration of tumor to vertebral bodies was observed (Fig. 3).

Figure 1

Preoperative frontal (A) and lateral (B) plain radiograph findings. Arrows in lateral image indicate translucency.

Figure 2

Preoperative coronal (A), sagittal (B), and axial (C, D) CT findings. L5 and S1 vertebral bone destruction can be seen. CT = computed tomography.

Figure 3

Preoperative T1 weighted (A), T2 weighted (B), and gadolinium contrast (C) MRI findings. Arrows indicate left/right common iliac arteries. Arrowhead indicates the inferior vena cava. A tumor can be seen at L5 and S1. The left/right common iliac artery and inferior vena cava are surrounded by the tumor. MRI = magnetic resonance imaging.

The diagnosis in this case was lumbosacral bone tumor due to direct extragonadal germ cell tumor infiltration. A 2-step operation was planned, with the first operation performed using instrumentation to fix the posterior side of the vertebral bodies (L3–S2). Two weeks later, using an anterior transperitoneal approach, the tumor was resected and the defect of vertebral bodies L5 to S1 was reconstructed directly in the operative field using PMMA cement (Fig. 4). We used PMMA cement that was not loaded with antibiotics because of the primary nature of the reconstructive surgery without evidence of infection. The retroperitoneal tumor was resected by a urologist, but there was strong adhesion between the tumor and left and right common iliac arteries. It was necessary to resect both the common iliac arteries, and a vascular surgeon replaced them with artificial vessels. During surgery, some damage to the left ureter also occurred and had to be repaired.

Figure 4

Postoperative plain radiographs. After posterior lumbosacral fixation, the tumor was resected and PMMA cement was used for vertebral body reconstruction. Plain radiographs show immediate postoperative (A, B) and postoperative 7 months (C), 27 months (D), and 33 months (E). Over time, the PMMA cement can be seen to move in an anterior direction, and 33 months after surgery, it had dislodged into the retroperitoneum. PMMA = polymethylmethacrylate.

Postoperative course

After surgery, the patient developed aspiration pneumonia, there was urine leakage from the damaged part of the ureter, and deep infection and sepsis developed. Bacterial tests detected Klebsiella in blood, methicillin-resistant Staphylococcus aureus in urine and Enterococcus at the wound site. A vascular surgeon removed the artificial vessels and performed an axillary-femoral artery bypass. The deep infection and sepsis were successfully treated with antibiotics and no post-infection recurrence was observed. No recurrence of the tumor was observed during the postoperative course.

At postoperative month 7, plain radiographs and computed tomography images showed hypertranslucency of bone surrounding the PMMA cement used to reconstruct the vertebral bodies. Subsequently, PMMA cement was observed to gradually migrate in an anterior direction and, 2 years 9 months after surgery, dislodged cement was observed to have penetrated the retroperitoneum (Figs. 4 and 5). Magnetic resonance imaging also showed anterior migration of PMMA cement over time and findings at postoperative year 2 suggested adhesion of the dislodged cement to the intestinal tract. The presence of dislodged PMMA cement in the intestinal tract was strongly suspected (Fig. 6). No posterior lumbosacral instrumental looseness or breakage was observed.

Figure 5

CT findings at postoperative 7 days (A, B), 7 months (C), 24 months (D), and 30 months (E). At postoperative 7 months, CT image showed hypertranslucency of bone surrounding the PMMA cement used to reconstruct the vertebral bodies. Over time, the PMMA cement can be seen to move in an anterior direction. CT = computed tomography.

Figure 6

MR image findings at postoperative 15 months (A), 24 months (B), 30 months (C), and 34 months (D, E). Arrows indicate suspected adhesion between the migrated PMMA cement and the intestinal tract. Arrowheads indicate dislodged PMMA cement. The presence of PMMA cement in the intestinal tract was suspected. PMMA = polymethylmethacrylate.

The patient developed nausea and abdominal pain and was readmitted to the hospital. Plain radiographs revealed intestinal gas niveau shadows. From contrast enema images, intestinal blockage with PMMA cement was strongly suspected (Fig. 7). Intestinal blockage due to dislodged PMMA cement was diagnosed, and a gastroenterological surgeon operated to remove the cement using the transperitoneal approach. PMMA cement was palpable in the small intestine, and an incision was made at the same location to remove it (Fig. 8). There was strong intra-abdominal adhesion, the peritoneum between the vertebral bodies and intestine could not be identified, and it was not possible to perform additional treatment for vertebral body defects. After surgery, the gastrointestinal symptoms resolved. No abdominal symptoms were observed 3 years after removal of the cement and blood tests and image findings showed no evidence of a recurrence of tumor or infection. Image findings also showed no evidence of posterior instrumental looseness or breakage (Fig. 9).

Figure 7

Plain radiograph (A) and contrast enema image (B). Arrowheads indicate niveau images. Arrows indicate dislodged PMMA cement. PMMA cement was suspected to have caused a blockage. PMMA = polymethylmethacrylate.

Figure 8

Findings at the time of PMMA cement removal (A, B). PMMA cement palpable in the small intestine (arrow) (A). An incision was made in the small intestine and the PMMA cement was removed (B). Findings of removed PMMA cement (smallest scale marks are 1 mm) (C, D, E). PMMA = polymethylmethacrylate.

Figure 9

Findings at 3 years after removal of the PMMA cement (A, B, C, D, E, F, G). The frontal (A) and lateral (B) plain radiograph findings. CT findings at the level of L4 (C) and S1 (D). The T1 weighted (E) and T2 weighted (F, G) MR image findings. No evidence of a recurrence of tumor, infection, or posterior instrumental looseness or breakage was observed in all images. CT = computed tomography.

Discussion

PMMA cement is often used as prosthetic material to compensate for bone loss after resection of limb bone tumors. In the field of spinal surgery, the use of PMMA cement for percutaneous vertebroplasty in the treatment of vertebral angioma was reported in 1987 by Galibert et al.[ Since then, PMMA cement has been widely used for vertebral body reconstruction along with metal cages following resection of spinal tumors and for vertebroplasty to treat vertebral fractures.[ The advantages of PMMA cement include its ability to match the shape of and fill areas of bone defect, the cytocidal effect on tumor cells that can be expected due to the heat of polymerization during hardening, and its high mechanical strength after hardening.[ In the case we examined here, PMMA cement was used directly in the defect of vertebral bodies for both purposes with reconstruction of anterior spinal column and the cytocidal effect on tumor cells after the resection of tumor. However, it has been reported that, since PMMA cement is mechanically stronger than bone tissue, there is a risk of fracture of reconstructed or adjacent vertebral bodies.[ There have also been reports of neurological symptoms developing due to the leakage and extravasation of cement from vertebral bodies,[ and the serious complications of pulmonary embolism or cardiac tamponade in the percutaneous vertebroplasty.[ For this case, taking into consideration its previously mentioned advantages, PMMA cement was used directly in the defect of vertebral bodies following tumor curettage using an anterior transperitoneal approach. Dislodgement of the cement could have occurred because, even though posterior instrumentation fixation was used, the fixation force between the L5 and S1 vertebral bodies was insufficient, resulting in persistent mobility in that region. Cement could also have become dislodged due to the influence of postoperative deep infection and the destruction of bone tissue around the cement. Since normal postoperative tumor marker values were maintained and no progression of bone destruction was observed after cement dislodgement, the possibility that dislodgement due to local recurrence of the tumor is unlikely. There have been reports of cases requiring removal of PMMA cement that has dislodged from the anterior spine.[ This is the first report of dislodged PMMA cement penetrating the alimentary canal. Fujibayashi et al[ reported a case of anterior cervical fixation in which the plate and screws penetrated the esophagus due to insufficient instrumentation fixation and traction on the alimentary canal resulting from postoperative infection and scar tissue. Furthermore, it has been known that the adhesion of tissues occur after radiotherapy. In the case we examined here, dislodgement of cement and penetration of the intestinal tract could have been due to the lack of mechanical stability of the reconstructed part and the formation and adhesion of scar tissue in the intestines and around the cement as the result of multiple abdominal operations using the transperitoneal approach, radiotherapy, and postoperative deep infection. It is thought that scar tissue reduced the mobility of the intestinal tract and that there was adhesion of cement and surrounding scar tissue to the intestinal tract, resulting in dislodgement of cement into the intestinal tract, causing a blockage. We concluded that the way of vertebral reconstruction after tumor resection should be selected in consideration of the property of the tumor, mechanical stability and vascularity of the reconstruction area, and the risk of infection, and that the way of anchoring the cement must be thoroughly planned when there is a need to use cement. In this case, we should have performed anchoring for the cement more strongly in the primary reconstructive surgery, and should have used a vascularized bone strut if it was possible to approach the vertebral body in the cement removal surgery, because the patient developed deep infection after the primary reconstructive surgery.

Conclusions

This was a rare case of PMMA cement dislodged into the intestinal tract and caused a blockage after its use in vertebral reconstruction following resection of a lumbosacral bone tumor using an anterior transperitoneal approach. When using bone cement to reconstruct vertebral bodies, the way of anchoring for the cement must be thoroughly planned to assure there is no dislodgement of cement.