An uncommon case of Mycoplasma hominis infection after total disc replacement

Abstract

Purpose: Beside mechanical complications, the majority of adverse events after total disc arthroplasty (TDA) are related to the surgical approach. Septic complications are very uncommon and only one previous case has been published. The objective of this article is to describe the clinical circumstances, treatment, and outcomes of septic complication after TDA at L4-L5, involving an uncommon pathogen (Mycoplasma hominis).

Methods: A 38-year-old woman underwent a MobiDisc(®) TDA at L4-L5 level for discogenic pain. One month postoperatively, she complained of acute low back and abdominal pain associated with fever (39 °C). C-reactive protein level was elevated (197 mg/L; normal <5 mg/L) and the white blood cell count was normal (7 × 10(9)/L; normal 4-10 × 10(9)/L). A computerized tomography (CT) showed a left psoas-based retroperitoneal abscess. Treatment consisted of open debridement, drainage and empirical antibiotic therapy. Intraoperative cultures yielded M. hominis after 7 days incubation. Antibiotic therapy was adapted and discontinued after 2 months. The patient had failed to mention earlier that she had been suffering from abnormal vaginal discharge for some time and was using an intrauterine contraceptive device.

Results: At 1.5-year follow-up, review confirmed healing of the infection with biological normalization without residual collection, radiolucent lines or osteolysis around the prosthesis at radiographs, CT and MRI.

Conclusions: Mycoplasma hominis can be involved as an extragenital pathogen in musculoskeletal infections. Because its culture and identification are difficult, special media and real-time PCR are required in case of postoperative deep wound infection after anterior lumbar spine surgery, especially in the case of previous genitourinary infections, to decrease the delay in diagnosis and treatment.

Fig. 1

Postoperative lateral view of MobiDisc at the L4–L5 disc level

Fig. 2

Computerized tomography showing left psoas abscess at the L4–L5 disc level (white arrow) 1 month after TDA

Fig. 3

Postoperative dynamic lateral views at 1.5-year follow-up of a well-functioning TDA. a Flexion and b extension. Range of motion is 8° at 1.5-year follow-up and was 2° postoperatively

Fig. 4

Computerized tomography 1-year after open debridement and drainage of a left psoas abscess at the L4–L5 disc level: no residual collection and no signs of periprosthetic osteolysis. a Frontal reconstruction b sagittal reconstruction

Fig. 5

Magnetic resonance imaging at 1-year follow-up showing no residual collection