Posterior Intertransverse Approach For Drainage Of Psoas Abscess Associated With  Spinal Tuberculosis

*Sanket Diwanji   # Gautam Zaveri

*Consultant Orthopaedic Surgeon, Akshar Purshottam Arogya Mandir & Muni Seva Ashram ,Goraj, Vadodara, India
#Consultant Orthopaedic Surgeon, Akshar Purshottam Arogya Mandir & Muni Seva Ashram ,Goraj, Vadodara, India

Address for Correspondence

Dr. Sanket R Diwanji,
B-201, Jaltarang Apartment,Halar Cross Road, Valsad,
GUJARAT, INDIA, 396001
Phone:919825658983
FAX:(02668)268048
E-MAIL: sanket_diwanji@yahoo.co.in

Abstract

Spinal tuberculosis is often associated with a pre or paravertebral abscess. In most instances, an abscess in the psoas muscle can be drained by CT/ Ultrasound guided aspiration, by endoscopy or by an open surgery during anterior debridement of the vertebrae. 
In two patients with dorsal spine tuberculosis where a posterior midline incision had been used for debridement, decompression and stabilization, we have extended the incision caudally and used an intertransverse approach to drain the associated psoas abscess. A thorough evacuation of the abscess was possible and both patients went on to heal uneventfully. 
The intertransverse approach has been routinely used for the excision of a foraminal disc herniation but its use has not been reported for the drainage of a psoas abscess. Operative technique, clinical feasibility and postoperative results are discussed.
Keywords: Inter transverse approach, psoas abscess

J.Orthopaedics 2006;3(1)e10

Introduction:

A psoas abscess is a common sequelae to tuberculosis of the dorsolumbar spine. Various methods of drainage of psoas abscess have been described. Open drainage can be done posteriorly through the Petit`s triangle, laterally by a flank incision parallel to the crest of the ilium, anteriorly under the Poupart ligament or by a Ludloff incision when the psoas abscess points subcutaneously in the adductor region of the thigh1.  Ultrasound or CT guided percutaneous drainage and retroperitoneoscopic drainage is also described2,3,4,5. 

We report two patients with tuberculosis of the dorsal spine who underwent a transpedicular decompression and instrumented stabilization. The concomitant psoas abscess was drained using an intertransverse approach after extending the posterior incision caudally. The intertransverse approach as described by Wiltse has gained popularity for removal of far lateral disc herniation6,7, but its application for drainage of psoas abscess has not been described.

Case Report:

Surgical Technique:

Case 1:

A thirty-two year old female presented with severe persistent lower dorsal back pain without neurological deficit. She had been treated with antituberculous drugs for eight months before coming to us, but continued to worsen. As shown in Fig.1, the  MRI scan revealed  destruction at  D11/12 vertebrae with a prevertebral abscess, abscess in epidural space, unilateral psoas abscess and a posterior paraspinal abscess. 

She was operated using a posterior midline incision. Bilatertal costotransversectomies were done at D11 level to drain the paravertebral abscess. The anterior lesion was then debrided through a transpedicular approach and cancellous graft from the laminae and spinous process was packed in the anterior defect. Posterior stabilization was done using a rod-screw construct from D10 to L1 vertebra.  The posterior paraspinal abscess was drained. The incision was then extended caudally up to the L3 vertebrae. As shown in Fig2 the intertransverse membrane was elevated between the L 2 & L3 transverse processes on the affected side. The psoas muscle appeared bulky. Pus was aspirated with a 16G needle to confirm location. The muscle was then incised and the abscess cavity was thoroughly evacuated. Approximately 400cc of thick pus was drained and the incision was closed over an intercostal (wide bore) drain. Postoperative period was uneventful. The drain was removed on the fifth post-operative day. Antituberculous drugs were continued for one year. The tuberculosis healed and she went on to a solid fusion. At twenty months follow-up she continues to do extremely well.

Case 2:

A twenty six year old male presented with pain in the lower dorsal region for one year, progressive weakness in the lower limbs and inability to walk with loss of bladder control. Examination revealed a painful gibbus at D9, grade 1 power in both lower limbs, hypoaesthesia below D10, with bladder involvement. As shown in Fig 4 his MRI scan showed destruction of D 9 vertebral body with kyphosis and severe spinal cord compression due to epidural granulation/ abscess. There was a prevertebral abscess extending from D 6 to D12 resulting in scalloping of the anterior surface of the vertebral bodies as well as bilateral psoas abscesses. The vertebral bodies were quite osteoporotic due to long standing disease. He had been treated with alternative medicines for 8 to 9 months and antituberculous drugs for 3 months before presenting to us with the above picture.  

He was operated through a posterior midline incision. Pedicle screws were inserted in D7, D8, D10 & D11 vertebrae.  Bilateral costotranversectomy enabled us to drain the prevertabral abscess. Through a transpedicular approach, the remnants of the D9 body with the D8/9 and D9/10 disc were excised and the spinal cord was decompressed. Cancellous chip graft obtained from the lamina was then loosely packed in the intervertebral area. Rods were assembled and compression was done in order to achieve a vertebral shortening (pedicle substraction) effect. Posterior decortication and bone grafting was done at the instrumented levels. The incision was extended into the lumbar spine. The intertransverse membrane was elevated bilaterally at L1/2 level and the approximately 250 cc pus was drained from the psoas abscess both on the right and the left. The wound was closed over a wide bore drain placed in both the psoas muscles. Drains were removed on the fifth post-operative day. The postoperative period was uneventful. Antituberculous drugs were continued. At 10 months follow-up, the patient is pain free, has fully recovered neurologically. Xrays showed early consolidation between D8 and D10. 

Discussion :

Spinal tuberculosis typically results in destruction of vertebrae and formation of soft-tissue abscesses that may eventually result in kyphotic deformity and neurological deficits. Surgery is aimed at debridement of the devitalized vertebrae, decompression of spinal cord/ nerve roots and spinal fusion. Anterior or posterior instrumentation is used to reduce the incidence of graft related complications as well as maintain sagittal alignment. A paravertebral abscess in the thoracic spine or a psoas abscess is often drained to reduce the bulk of diseased tissue and promote healing. Whilst anterior instrumentation to supplement anterior fusion is an accepted procedure, anterior instrumentation may not be adequate in patients with severe osteoporosis (due to long standing disease), or where there is involvement of multiple vertebrae. Occasionally anterior surgery may be contraindicated because of medical or anaesthetic reasons. In these patients either an anterior debridement/ decompression & fusion may be followed by a posterior instrumentation 8,9 or a posterolateral (transpedicular) debridement and decompression may be supplemented by a posterior instrumentation 10.    

A psoas abscess associated with dorsal spine disease may not be adequately drained through the transthoracic approach used for decompression since the pus is very thick and there may be septa and loculations 11. It may require to be drained separately either endoscopically or through a separate incision in the Petit`s triangle posteriorly, along the crest of the ilium laterally or under the Poupart ligament anteriorly. This requires a second incision and increases the duration of surgery and overall morbidity. Such large abscesses usually cannot be drained adequately by percutaneous technique. 

Wiltse & Spencer described the paraspinal approach to the lumbar spine which involves longitudinal separation of the sacrospinalis muscle group to expose the posterolateral aspect of lumbar spine12. The intertransverse membrane is then elevated from its attachment to the transverse processes to visualize the exiting nerve root and excise a far lateral disc herniation.  As illustrated in Fig6, anatomically the psoas muscle takes origin from the anterior surface of the transverse processes of the lumbar vertebral bodies. Thus once the intertransverse membrane is elevated, the muscle seen immediately anteriorly is the psoas muscle. An incision made on the posterior surface of the muscle enables us to access the abscess cavity and thoroughly drain the abscess leaving behind a wide bore drain for further drainage post-operatively. In Case no1, the patient had D11/12 tuberculosis with prevertebral, epidural, right posterior paraspinal abscess/ granulation with a huge abscess in the right psoas muscle. Using the traditional anterior approach, she would have required a right sided anterior transdiaphragmatic approach for debridement, decompression and drainage of the psoas abscess followed by a drainage of the posterior paraspinal abscess. Besides the long standing disease had resulted in significant osteoporosis of the vertebrae, so that the likelihood of problems with anterior instrumentation was higher. Through the posterior approach, we were able to drain the paraspinal abscess, the prevertebral abscess, perform a transpedicular debridement, decompression and instrumented fusion. Finally by elevating the intertransverse membrane in the lumbar spine, we identified the psoas muscle and under vision drained it completely thereby fulfilling all the aims of the surgery through a single, cosmetic incision whilst reducing the morbidity associated with a combined anterior & posterior procedure. 

In case 2, the patient had destruction of D9 with spinal cord compression. His vertebral bodies were again very osteoporotic and the anterior surfaces of the bodies from D6 to D12 were scalloped because of the pressure from the longstanding anterior paravertebral abscess. Anterior instrumentation alone in these circumstances would have a high risk of failure. Besides separate incisions would be required to drain the large bilateral psoas abscesses. Here again we elected to perform the entire procedure posteriorly. We instrumented from D7 to D11, drained the prevertebral abscess by bilateral costotransversectomy at D9, then resected the D9 vertebra through a transpedicular approach and finally compressed between the cephalad and caudad screws to achieve vertebral shortening. The last step was to extend the midline incision downwards and through a bilateral intertransverse approach between L1 and L2, drain both the psoas abscesses. Again the entire procedure was safely performed through a single incision.

Thus in both instances, we found that the intertransverse approach directly led us to the psoas abscess cavity. We were able to evacuate the cavity thoroughly and leave a wide bore drain for evacuating subsequent collection. In patients with a dorsal or lumbar tuberculosis, where posterior surgery is being contemplated, the intertransverse approach is an easy, safe and efficient method to drain the associated psoas abscess through the same posterior skin incision. This reduces duration and morbidity of surgery. Further bilateral psoas abscess can be drained through a single incision

Conclusion:

In patients with dorsal or lumbar spine tuberculosis undergoing a posterior debridement, decompression and stabilization, the intertransverse approach permits excellent drainage of the psoas abscess through an extension of the same posterior midline incision and without any significant additional morbidity.

Reference : 

1. Campbell’s operative orthopaedics.10th edition, page 2047

2. Dinc H  ,Onder C , Turham A U , Suri A, Aydin A, Yulung G Gumele HR .Percutaneous catheter drainage of tuberculous and non tuberculous psoas abscess. Eur. J. Radiology.1996 Sep ; 23(2):130- 4

3. Gupta S, Suri S, Gulati M, Singh P .Ilio-psoas abscess :percutaneous drainage under image guidance. Clin Radiology 1997 Sep;52(9):704-7

4. Katara AN, Shah RS, Bhandarkar DS, Unadkat RJ. Retroperitoneoscopic drainage     of a psoas abscess. J. Paediatr.Surg.2004 Sep;39(9)C 4-5

5. Kang M ,  Gupta S, Gulati M, Suri S .Iliopsoas abscess  in the paediatric

6. Population: treatment by US –guided percutaneous drainage.  Paediatr  Radiol.1998 Jun; 28(6): 478-81

7. Greiner-Perth R, Bohm H, Allan Y. A new technique for the treatment of lumbar far lateral disc herniation technical note and preliminary result .Eur. Spine J.2003;12(3):320-4 Epub 2002 Dec 11

8. Hodges S D, Humphray   SC, Eck J C, Covington LA .The surgical treatment of far lateral L 3-4 & L4-5 disc herniations modified technique & outcome analysis of 25 patients. Spine.1999 Jun 15;24(12):1243-6

9. Mukhtar AM , Farghaly MM, Ahmed SH. Surgical treatment of thoracic and lumbar tuberculosis by anterior interbody fusion and posterior instrumentation. Med  Princ  Pract .2003 Apr-Jun;12(2):92-6.

10. Benli I T , Akalin S ,Citak Kis  M, M, Kanevetei S , Duman E,. The results of anterior radical debridement and anterior instrumentation in pott’s disease & comparison with other surgical techniques. Kobe J  Med. Sci. 2000 Apr; 46 (1-2) :39- 68

11. Mehta JS, Bhojraj SY Tuberculosis of thoracic spine A classification based onthe selection of surgical strategies. J.Bone Joint Surg Br.2001 Aug;83 (6):859-63

12. Iwaki H,  Mori H,  Kajita Y, Yoshida T, Yamayuchi T. Giant psoas abscess with aggressive extension: report of a case. Hinyokiko Kiyo.1999 Dec;45 (12) :835-7

13. Wiltse LL, Spencer CW; New uses & refinements of the paraspinal approach of the lumbar spine, Spine 13:696, 1988

This is a peer reviewed paper 

Please cite as : Sanket Diwanji: Posterior Intertransverse Approach For Drainage Of Psoas Abscess Associated With  Spinal Tuberculosis

J.Orthopaedics 2006;3(1)e10

URL: http://www.jortho.org/2006/3/1/e10

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