International

International Orthopaedics (SICOT) (1992) 16: 152-156

Orthopaedics ©Spfinger-Veflag 1992

Failed lumbar spinal surgery S. Dhar and R. W. Porter The Department of Orthopaedic Surgery, Doncaster Royal Infirmary, England

Summary. Failures and poor results of 160 patients after lumbar spinal surgery between 1980 and 1984 were analysed retrospectively. A self-rated questionnaire carried out 12 months after operation revealed 20poor results; these occurred most commonly after multiple operations, decompression and fusion as compared to disc excision. The commonest cause was failure to recognise abnormal pain behaviour before operation. A more careful preoperative assessment should reduce the incidence of failure.

disabled and difficult to m a n a g e [3, 19]. B e s i d e the morbidity, the i m m e n s e s o c i o e c o n o m i c implications are self-evident. T h e present r e v i e w analyses the patients' subjective results one y e a r after operation. A n attempt is m a d e to identify the patients with p o o r results and the reasons for failure, and to p r o p o s e suitable m a n a g e m e n t for them.

R ~ s u m ~ . L'dtude rdtrospective de 160 opirds du

rachis lombaire, de 1980 it 1984, & l'hOpital gdndral de district, a permis d'analyser les dchecs et les mauvais rdsultats. Grgtce it un questionnaire adressd it ces malades un an aprds l'intervention on a pu retrouver 20 mauvais rSsultats. Ces vingt cas ont dtd rdexaminds afin de d~terminer la cause de ces dchecs. I1 y avait davantage de mauvais rdsultats apr~s chirurgie itrrative, aprds ddcompression et arthrodOse qu' aprds simple discectomie. La cause habituelle de ces ~checs ~tait une mdsestimation, lots de l'examen prd-opdratoire, d'une rdaction anormale it la douleur. Il semble qu'un examen plus attentif des patients lombalgiques puisse diminuer le nombre des 6checs du traitement chirurgical.

E v e r y reported series o f l u m b a r spinal surgery for low b a c k pain and sciatica contains a hard core o f patients with p o o r results. This g r o u p are severely

Reprint requests to: S. Dhar, University Department of Orthopaedic and Accident Surgery, Royal Liverpool Hospital, Prescot Street, PO Box 147, Liverpool L69 3BX, UK

Patients and methods We reviewed the medical records and radiographs of patients who had spinal operations between January 1980 and December 1984 at our hospital. This included a self-rated questionnaire, completed by each patient twelve months after operation, which recorded the degree of their recovery of normal function at home, at work and in recreation, the presence or absence of back or leg pain, their current drug therapy, and their satisfaction with the result of the operation. Each patient was then classified as excellent, good, fair or poor (Table 1). All the operations were carried out by the senior author (RWP). The results of disc excision, decompression for central or lateral canal stenosis, fusion for spinal instability, and multiple spinal operations were compared. Those with poor results were then reviewed in an attempt to identify the cause of failure. This review was conducted in three parts with a survey of the clinical course before operation; an assessment of the operative procedure, and an analysis of the postoperative course. The original diagnosis was reconsidered, and the adequacy of the surgery, with the possible failure to deal with the pathological lesion, was taken into account. Evidence of abnormal pain behaviour [27] was sought with particular attention to inappropriate signs (Fig. 1) and any psychological disturbance was assessed by the Minnesota multiphasic personality inventory (MMPI). Specific questions were asked about the financial implications of the disability. When necessary, further investigations were carried out including radiography, CT scanning, radiculography and electrodiagnostic tests, such as fibrillation potentials and ankle reflex latencies [11].

S. Dhar and R. W. Porter: Failed lumbar spinal surgery

153

Table 1. Criteria for assessment of results

Ax~lbadi~

Result

Criteria

Excellent Good

No pain, no functional limitation Intermittent pain in the back or leg, no functional limitation at work, home or in recreation, no analgesics Intermittent pain in back or legs, and either affecting function at work, home or in recreation, or use of analgesics Constant pain in back or legs, or daily analgesics, or would not have had the operation in retrospect

Fair

Poor

Non-dormatomai slmoey kms

Inappropriate

Results

One hundred and sixty patients who had spinal operations completed the questionnaire; 26 had been lost to follow up. The results are shown in Table 2. Most operations were excision of discs and there were fewer poor results in this group than after other procedures. Repeated operations were the most disappointing. Twenty patients with poor results were reviewed and the causes of failure are suggested in Table 3. They all complained of low back pain, 18 had more than 50% limitation of lumbar movement, and one had signs of nerve root irritation or tension. Two patients had a persistent motor neurological had deficit which was slight in one; both had had further operations. Three patients, who were treated by decompression for spinal stenosis, had persistent stenosis and would have benefited from a more extensive decompression initially (Fig. 2). Two others were thought to have symptoms due to a central canal stenosis; radiculography showed dural encroachment and a further decompression was carried out in spite of signs of abnormal pain behaviour. One patient benefited temporarily from an anterior fusion, but a subsequent posterior fusion, although sound, failed to relieve her pain. Another was

Resisted hip fklxkm

Widespread tenderness

Fig. 1. The six inappropriate signs

thought to have an unstable segment, but continued to have pain after a sound fusion. A pseudarthrosis followed one attempted fusion. Two had signs of irreversible root damage on electrical testing, in spite of an adequate decompression on a second occasion. Four had evidence of epidural fibrosis, but in only one was it considered to be severe enough to be responsible for symptoms. Two patients would have lost financially if their operation had been successful. Thirteen of the 20 patients showed a significant psychological disturbance as judged by the symptoms, clinical examination, and investigations, in-

Table 2. Comparison of results of each operative category Operations

Discectomy Decompression Fusion Multiple spinal Surgery

Number

86 36 16 22

Result (%) Excellent

Good

Fair

Poor

25 (29) 4 (11) 2 (12) 1 (5)

44 (51) 7 (19) 8 (50) 4 (18)

14 (16) 18 (50) 3 (19) 10 (45)

3 (4) 7 (20) 3 (19) 7 (32)

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S. Dhar and R. W. Porter: Failed lumbar spinal surgery

Table 3. Causes of failure in 20 patients No.

Operation

Age (years)

Iatrogenic causes EF

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. I 1. 12. 13. 14. 15. 16. 17. 18. 19. 20.

Discectomy Discectomy Discectomy Decompression Decompression Decompression Decompression Decompression Decompression Decompression Fusion Fusion Fusion Multiple operations Multiple operations Multiple operations Multiple operations Multiple operations Multiple operations Multiple operations

32 27 43 59 62 53 60 49 58 69 52 41 45 59 60 43 52 45 40 51

. + . +. . . . +. . . . +.

IRD

ID .

.

. . .

. . .

. .

. .

. .

. . . . . .

.

. -

.

.

-

-

+

.

. . . .

.

+-

.

. .

Psych. causes

Financial implications

+ + +. +. ++++

-

-

-

-

+ + -

+ -

+ + -

+ -

PSEUD

+ + + .

APB

.

. . . . .

+ +

.

. .

. + ++++ + +

.

EF: epidural fibrosis, ID: inadequate decompression, Pseud: pseudarthrosis, IRD: irreversible root damage, APB: abnormal pain behaviour, Psych.: psychiatric, +: present, -: absent, +-: maybe present

cluding M M P I . T h e y suffered f r o m depression, anxiety, h y p o c h o n d r i a s i s and c o n v e r s i o n manifestations. As this w a s a retrospective study, it was not possible to determine w h e t h e r or not these s y m p t o m s w e r e the cause or the effect o f the p o o r o u t c o m e o f the operations.

Discussion T h e i n c i d e n c e o f failure after l u m b a r spinal operations is still d i s a p p o i n t i n g l y high, in spite o f sophisticated investigations and i m p r o v e d m e t h o d s o f assessment n o w available. Failure is easily r e c o g nised b y the patient w h o is the best j u d g e o f the result. Short t e r m results can give a false i m p r e s s i o n o f success [17] and its i n c i d e n c e can be m a n i p u l a t e d b y the questionnaire [8]. It has b e e n s h o w n that limited i n f o r m a t i o n i m p r o v e s the reliability o f the a s s e s s m e n t [18]; our questionnaire was therefore simple and our criteria few. Failure at t w e l v e m o n t h s is u n m i s t a k a b l e with c o n t i n u o u s pain, the daily use o f analgesics, or a patient, w h o with hindsight, says he w o u l d not h a v e had the operation. T h e results w e r e less p o o r after disc excision, o n l y 4 % w e r e unsatisfactory, b e c a u s e the indications for operation are n o w clearly defined [14, 29]. I f pain is not relieved b y a d e q u a t e rest, and the level is conf i r m e d b y r a d i c u l o g r a p h y or a C T scan, an operation carried out to relieve r o o t tension will be f o l l o w e d b y rapid r e c o v e r y [6].

O n e o f our patients, w h o had a disc excision, was relieved o f root pain, but c o n t i n u e d with b a c k pain referred to the leg f r o m an u n s u s p e c t e d unstable segment. T h e t w o patients with irreversible root d a m age, c o n f i r m e d b y electrodiagnostic testing [11, 15], failed to r e s p o n d to adequate d e c o m p r e s s i o n . Unfortunately, the criteria for fusion and d e c o m pression are less exact. It is difficult to estimate h o w extensive a d e c o m p r e s s i o n needs to be f r o m m y e l o g r a p h y and C T scans. T h e canal will h a v e b e e n narr o w e d for several years b e f o r e s y m p t o m s develop, and a l t h o u g h stenosis m a y be present at several levels, the lesion c a u s i n g s y m p t o m s is p r o b a b l y localised (Fig. 3). It is essential to ensure that this s e g m e n t is d e c o m p r e s s e d [22, 31], and it is t e m p t i n g to rely on the i m p r e s s i o n during operation that the tight dura and roots are given adequate space. O n the g r o u n d s o f safety, it m a y be wise to be m o r e radical than seems n e c e s s a r y [12], but better results h a v e b e e n reported after a one- or two-level d e c o m p r e s sion for localised s e g m e n t a l stenosis than for a three-, four- or five-level d e c o m p r e s s i o n for multisegmental disease [5]. S o m a t o - s e n s o r y e v o k e d potentials m a y help in assessing the correct level during operation [2]. T h e incidence o f iatrogenic lesions w a s small, but m a y increase with a l o n g e r f o l l o w up. Extradural fibrosis was responsible for s y m p t o m s in one o f the f o u r patients in w h o m it o c c u r r e d (Fig. 4), in spite o f the dura being c o v e r e d with a fat graft [10]. T h e

S. Dhar and R. W. Porter: Failed lumbar spinal surgery

Fig, 2. Lateral radiograph showing disc degeneration with traction spurs and retrolisthesis. The double shadow of the posterior vertebral border suggests some rotational displacement. One root can be affected in the root canal, and another in the central canal at the cranial lip of the lamina and in the lateral recess; both need to be decompressed

155

occludes the metramazide column. Should L 3/4 also be decompressed? Fig. 4. Radiculogram of a patient who still has root symptoms after decompression for spinal canal stenosis. There is epidural fibrosis, and the root sheaths on the right side particularly failed to fill

Fig. 3. Lateral radiculogram of a 60 year old man with symptoms of neurogenic claudication. Degenerative spondylolisthesis

Fig. 5. A C T scan of a 34 year old women who had a left sided disc protrusion excised through a fenestration 2 years previously. Symptoms had been completely relieved until right sided root symptoms developed. She had no inappropriate signs. The scan showed a new right sided disc protrusion (arrow) which was excised with a good result

significance of the fibrosis is debatable as it was found in 75% of CT scans after operation [24]. The commonest cause of failure was not due to inadequate operation or iatrogenic complications, but to incorrect assessment of the patient. In seven

failures, a lesion was found at operation which was thought to be causing symptoms, but abnormal pain behaviour had been ignored. Four of these patients had a depressive illness. A population with low back pain has a high proportion of individuals with psychological and psychotic disturbances [13] which may only become apparent when chronic invalidism has followed operation [16]. Litigation and a treatable condition can coexist, but a pending claim for compensation may have a negative effect on the result of operation [4, 26]. The problem is to interpret the significance of a lesion in a distressed patient; abnormal pain behaviour may mask a treatable condition, but the abnormality found by radiculography or CT scan may not be causing symptoms. Failure may follow when the decision to operate is influenced by the degree of distress, or by the presence of abnormal investigations, rather than by abnormal objective signs [28]. Thirteen of the twenty poor results had signs of abnormal pain behaviour twelve months after operation; this may be the effect of having to cope with a painful back, but most had the same problem before operation when a treatable lesion was thought to coexist. The result of a second intervention after a failed lumbar spinal operation is unpredictable [3, 23]. Although four of our failures had possible physical causes, most failures had been re-operated on be-

156

cause of the presence of a lesion which was mistakenly thought to be responsible for their distress, and there were inappropriate signs (Fig. 1). A detailed psychological assessment should be carried out before all re-operations. There is no evidence that the MMPI low back scale will differentiate between those patients who will have a poor, fair or good outcome after spinal fusion [30], or from decompression [7], nor does it identify non-organic from organic low back pain [25], but an abnormal profile directs the surgeon's attention to factors other than the spine which may be responsible for low back pain. It does not necessarily mean that a second operation will fail, but the operation can only be justified if both patient and surgeon are aware of the risks (Fig. 5). There are possible benefits for a multidisciplinary approach before a second operation, involving a psychologist, anaesthetist, radiologist, general practitioner, spouse and surgeon [1]. Assessment will take time, but nevertheless it should be comprehensive as further failure will compound the patient' s problems. Management of patients in whom a spinal operation has failed is difficult. The most recalcitrant problem is the patient who has had several operations, but surgeons should not operate on pain as such. A further operation will only help if the original diagnosis was wrong or the surgery inadequate, or if there are iatrogenic complications. One of our patients with epidural fibrosis was referred to a pain clinic for epidural injections [9], but most of our failures showed abnormal illness behaviour for which invasive treatment would have been counterproductive. Four patients had psychiatric help and three entered a behaviour modification programme with moderate success [20, 21]. The remainder were told frankly, after full investigation, that further treatment was not likely to be effective and they were discharged to their general practitioner. Failure will always be with us. We suggest that its incidence will be reduced, not by more sophisticated investigation of the patient's back, but by a more careful clinical and psychological assessment. References 1. Bartorelli D (1983) Low back pain - a team approach. J Neurosurg 15:41-44 2. Britt RH, Ryan T (1986) Use of a flexible epidural stimulating electrode for intra-operative monitoring of spinal somato-sensory evoked potential. Spine 11: 348- 351 3. Connolly JF (1983) Does operative treatment of lumbar disc syndrome produce more disability than it prevents? Nebraska Med J 1: 155-156 4. Finnegan BE, Rothman RH, Fenlin JMJ, Marvel JP, Nardini R (1975) Litigation has an adverse effect in outcome of surgery. J Bone Jt Surg [Am] 57:1034

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