Indications for surgical intervention in spinal tuberculosis

Absolute indications:

Watts has listed the absolute indications for surgery in tuberculosis of the spine as:

• Marked neurologic deficit related to severe kyphosis, retropulsed bone or retropulsed disc.
• Large cervical abscesses in a patient in whom respiratory obstruction has developed.
• Progression of neurologic deficit despite adequate chemotherapy.
• Progression of kyphosis or instability despite adequate =chemotherapy.

Relative indications:

• Inability to obtain material for culture by other means.
• Neurologic deficits in patients for whom prolonged bed rest may give =rise to other problems.
• Persistent pain or spasticity.
• Pain related to spinal instability where spontaneous fusion has not =occurred.

With regard to spinal tuberculosis and its management, the following are some of the points noted in recent (and not so recent) literature.

Tuberculosis of parenchymatous organs is characterised by a high bacterial count while that of bone by a low one. Therefore resistant mutants in spinal disease are fewer and drug therapy is usually effective. One contributor suggested that it would be justified to treat Potts paraparesis in Iraq or India with antimicrobials alone because of the sheer number of cases seen and certainty of the diagnosis. TB spine is paucibacillary in nature and the final diagnosis rests on histology. Because of the rarity of the condition here, it would be unwise to treat this case with drugs alone. Moreover it takes about 6-8 weeks for the drugs to become effective and show clinical improvement. It is questionable if one could wait that long in this situation. Surgical debridement and anterior fusion perhaps would be a more rational approach.

The question of choice of treatment of uncomplicated spinal tuberculosis has been to some extent answered by the series of clinical trials carried out by MRC Working party. The studies were conducted on patients with active disease in the thoracic or lumbar spine who were all placed on chemotherapy regimes and categorised into various groups as follows:

1.In Masan (Korea):

Patients treated with ambulant/outpatient chemotherapy

Those who received =6 months of bed rest in the hospital with chemotherapy.=20

2. In Pusan (Korea):

Patients placed in a plaster jacket for 9 months versus=20

Those who were not.

3. In Bulawayo :

Patients who received only ambulant chemotherapy versus

Those submitted to chemotherapy plus open debridement.

4. In Hong Kong :

Patients who were treated with open debridement versus
Those who underwent radical debridement and fusion (anterior spinal fusion)

The results of the trial were:

1.Nonoperative treatment led to a favourable status in 67% at 18 months, 85% at 3 years and 88% at 5 years. 6 months of bedrest or plaster jacket did not make any difference in the results.

2.Debridement plus chemotherapy both in Bulawayo and in Hong Kong gave no better results than those of ambulant treatment in Korea and in Bulawayo, except that a favourable status tended to be established rather earlier in 80% of cases at 18/12. Results at 5 years were the same.

3.Radical operation with chemotherapy showed no advantage except that a favourable status was achieved quickly in a large proportion of patients ie 89% at 18/12. However it was also noticed that bony fusion occurred more often and kyphosis showed no increase. Therefore the MRC recommended that uncomplicated spinal tuberculosis be treated by adequate chemotherapy and radical operation be used only if surgical expertise, and other facilities existed.

Griffiths, who headed these trials said the following about tuberculosis of the spine complicated by paraplegia:

"....although many cases of paraplegia in active disease will respond to conservative treatment....early decompression is wise as penetration of the dura mater and compression of the cord by an intradural abscess is common..."
"....paraplegia in healed disease is a much more difficult therapeutic problem...there is nothing to hope from chemotherapy...it seems reasonable to advocate removal of internal gibbus and full anterior decompression of the cord..."

Tuli in 1975 published his personal results of treating patients with and without paraplegia on the so-called "middle path regime" and showed that indications for surgery dropped to 60% in those neurologically compromised and to 6% in those with normal neurology. Thus it was shown that neurological recovery was possible with chemotherapy alone although surgery became indicated at times.

With regard to the progression of deformity in the sagittal plane there have been a couple of outstanding papers:

Rajsekaran and Shanmugasundaram while conducting the Madras study of tuberculosis of the spine described a technique of predicting the ultimate gibbus angle at final healing in patients treated non-surgically. The formula is Y=3DA+Bx, where y is the final gibbus angle, A and B are constants (5.5 and 30.5) while x represents the initial loss of body height. They recommended that their formula be used to predict the final angle and radical surgery be offered if the deformity is unacceptable. Finally Upadhyay et al. from Hong Kong have shown that the mean kyphus angles show correction after radical surgery and that in the long term the correction remains maintained.

The latest British Bone and Joint has published the 15-year assessment of clinical trials conducted by the MRC working party. The message in their own words is "......the earlier results of these trials are confirmed by the long-term follow-up with no late relapse or late-onset paraplegia. The results of chemotherapy on an outpatient basis were not improved by bed rest or plaster jacket and the only advantage of the radical operation was less late deformity compared with debridement." "......short-course regimes based on isoniazid and rifampicin are as effective as the 18-month regimes : ambulatory chemotherapy with these regimes should now be the main management of uncomplicated spinal tuberculosis."

=References:

Griffiths D LL The treatment of spinal =tuberculosis in :McKibbin B, ed. Recent advances in orthopaedics 3.1979.1-17.

Tuli S M Results of treatment of spinal tuberculosis by "middle path regime". JBJS(B)1975;57-B:13-23.

Rajasekaran S and Shanmugasundaram T K. Prediction of the angle of gibbus deformity in tuberculosis of the spine.JBJS(A) 1987;503-509.

Upadhyay S S,Saji M J,Sell P,Sell B,Yau A C Longitudinal changes in spinal deformity after anterior spinal surgery for tuberculosis of the spine in adults. A comparative analysis between radical and debridement surgery. Spine 19(5):542-9,Mar 1994.

MRC Trial JBJS(B)1998;80-B:456-62

Watts HG, Lifeso RM Current Concepts Review; TB of Bones and Joints. JBJS 78-A No 2 288-295. Feb 1996