The efficacy of negative pressure wound therapy in treating sacroiliac joint tuberculosis with a chronic sinus tract: a case series

There were seven female and five male patients included in the study. The average
patient age was 32.8 years (range, 21 to 63 years), and the average length of follow-up
was 37.1 months (range, 24 to 54 months).

All 12 patients complained of persistent buttock or low back pain, a chronic sinus
tract, and difficulty walking. Ten (83.3 %) patients had typical symptoms of tuberculosis
infection including weight loss, poor appetite, fever, and sleep hyperhidrosis. The
pelvic compression test and Gaenslen’s test was positive on the affected side of all
patients. Pain of the hip can be induced by hip over flexion and over extension. Four
(33.3 %) patients had undergone abscess drainage or curettage before admissions. One
(8.3 %) patient had bilateral sacroiliac joint tuberculosis, and seven (58.3 %) patients
had left and four (33.3 %) had right sacroiliac involvement.

The sacroiliac joints of all patients were stable. Sinus tracts were found in all
patients, including the buttocks in 11 (91.7 %), groin in 1 (8.3 %), and perineum
in 1 (8.3 %). Eleven (91.7 %) patients had a single sinus tract, and 1 (8.3 %) patient
had two. Five (41.7 %) patients had tuberculosis in other sites; two (16.7 %) patients
had active pulmonary tuberculosis, and one (8.3 %) had infection at T10, L5, and in
the intestine, respectively. Four (33.3 %) patients had prior surgery; three (25 %)
had undergone abscess drainage and one (8.3 %) curettage. One (8.3 %) patient had
a history of sacroiliac joint tuberculosis 16 years previously. No patient was infected
with HIV (Table 1).

Table 1. Clinical features

All patients were treated with NPWT according to the site and the size of the sinuses.
The average duration of symptoms was 12.41?±?4.36 months (range, 9 to 24 months).
The average time interval between onset of low back pain and sinus tract formation
was 8.50?±?4.56 months (range, 3 to 20 months). The average duration of sinus tract
drainage was 3.92?±?1.08 months (range, 3 to 6 months). Patients received regular
anti-tuberculosis therapy for a mean of 4.67?±?1.37 months (range, 2 to 7 months)
before admission. Patients were treated with NPWT for an average of 18.33?±?6.97 days
(range, 14–35 days). Sinus tract closure was observed after the initiation of NPWT
at an average of 25.25?±?7.23 days (range, 2042 days).

Culture in one (8.3 %) patient was positive for methicillin-resistant Staphylococcus aureus (MRSA) resistant to ampicillin, pefloxacin, ceftazidime, gentamicin, and ciprofloxacin.
Vancomycin was used to treat this patient. One sinus culture revealed Staphylococcus epidermidis, and appropriate antibiotic treatment was initiated.

Fifty percent (6/12) of patients had positive cultures for M. tuberculosis. Of them, 33 % (2/6) were multi-drug resistant tuberculosis (MDR-TB). Of the six
positive tuberculosis cultures, 33.3 % (2/6) were resistant to isoniazid, 33.3 % (2/6)
to rifampicin, 16.7 % (1/6) to streptomycin, 16.7 % (1/6) to pasiniazid, and 16.7 %
(1/6) were resistant to rifapentine. Resistance to three drugs was found in one case,
and resistance to four drugs was found in one case. Anti-tubercular drugs were modified
in two patients based on sensitivity testing after their wounds healed.

During the control phase, the duration of dressing changes was 30 days. The average
daily drainage volume, wound volume, ESR, and CRP changed from 21.75?±?8.86 to 21.33?±?7.90 ml,
37.75?±?33.80 to 35.17?±?37.44 cm
³
, 40.16?±?23.99 to 38.25?±?21.63 mm/h, and 32.33?±?12.09 to 33.33?±?13.36 mg/dl, respectively.
The average reduction of wound volume following treatment was 6.45 %.

During the 7 days of the interphase, the average daily drainage volume, wound volume,
ESR, and CRP changed from 20.75?±?6.94 to 22.33?±?7.28 ml, 35.17?±?37.44 to 34.08?±?33.91 cm
³
, 38.25?±?21.63 to 38.33?±?20.82 mm/h, and 33.33?±?13.36 to 33.67?±?11.72 mg/dl, respectively.
There was no significant difference of the change in the drainage volume, wound volume,
ESR, and CRP in the control phase and interphase (P??0.05).

In the intervention phase, average duration of NPWT was 18.33?±?6.97 days (range,
14–35 days). The average drainage volume increased from 22.33?±?7.28 to 29.17?±?16.63 ml
during the first 3 days. After that, the average daily drainage volume decreased from
29.17?±?16.63 to 0.25?±?0.87 ml on the 35th day. The average wound volume changed
from 34.08?±?33.91 to 25.50?±?26.04 cm
³
(P??0.05). The average reduction of wound volume following the treatment was 26.98 %.
The average ESR changed from 38.33?±?20.82 to 25.50?±?11.72 mm/h (P??0.05). The average CRP changed from 33.67?±?11.72 to 13.00?±?8.01 mg/dl (P??0.05). The reduction in average wound volume, ESR, and CRP were greater in the
intervention phase than in the control phase (P??0.05) (Figs. 2 and 3; Table 2).

Fig. 2. Daily drainage volume. DC dressing change, NPWT negative pressure wound therapy

Fig. 3. Comparison between mean ESR, CRP, and wound volume after admission. The data are expressed
as mean?±?standard deviation (SD)

Table 2. Wound volume, ESR, and CRP of patients who received dressing changes or NPWT

ESR and CRP returned to normal by 3 months following discharge. Anti-tuberculosis
therapy was administered for an average of 14.00?±?2.95 months (range, 12–18 months).
Definitive bony fusion was observed in five (41.7 %) patients and fibrous ankylosis
in 7 (58.3 %) (Figs. 4 and 5). The average time to bony fusion was 41.20?±?9.23 months (range, 30–54 months).
All sinus tracts healed without recurrence. At final follow-up, one (8.3 %) patient
had a little discomfort occasionally. No other complications occurred.

Fig. 4. a Sinus tracts in the left buttock. b Management with NPWT. c MRI of the sacroiliac joints: erosive changes and abscess involving the right sacroiliac
joint and sinuses in the left buttock. d MRI demonstrating healed abscesses and solid bony fusion 36 months after NPWT and
anti-tubercular therapy

Fig. 5. a Sinus and wound in the left buttock. b Management with NPWT. c Formation of fresh granulation tissue after NPWT. d CT scan of sacroiliac joints: erosive changes involving the right sacroiliac joint.
e CT scan demonstrating bony fusion 30 months after NPWT and anti-tubercular therapy