Aeta Neuroehirurgiea 33, 311--317 ( 1976 ) 9 by Springer-Verlag 1976

Neurosurgieal Clinic of the University of Sassari, Italy (Director: Prof. G. L. Viale)

Redundant Nerve Roots of the Cauda Equina A Case

Report By

A. Pau and S. Turtas With 2 Figures

Summary One further case of redundant nerve roots ed, and a review of eleven comparable cases In the authors' opinion, this disease appears frequently but not necessarily associated with

of the eauda equina is describin the literature is provided. to be a congenital anomaly, spinal changes.

I~edundant nerve roots of the eauda equina have rarely been found at operation. I n a recent review of the literature (Sorensen and Wirthlin 1975) five eases were quoted. I t has been stressed t h a t signs and symptoms, as well as myelographic findings, m a y lead to an erroneous preoperative diagnosis of arteriovenous malformation of the spinal cord or disc lesion. Although hypothetical views about aetiology and pathogenesis of this rare condition have been p u t forward, there still remains considerable uncertainty. The present ease seems worth reporting because of the r a r i t y of the diseorder.

Case Report A 61 year-old man, in August 1964, experienced an episode of excruciating right sciatica associated with weakness of the right leg. No history of back trauma was reported. Spontaneous resolution occurred in a few days, but later, periods of good health alternated with relapses of pain and motor weakness. The patient had been admitted to various orthopaedic centres where he was treated with bed rest and analgesics. During the previous two years, frequent low back pain radiating down the right leg disabled the patient for long periods of time, and motor power in the limb deteriorated. No sphincter disorders occurred.

312

A. P a u and S. T u r t a s :

On S e p t e m b e r 3, 1974, 10 years after the onset of s y m p t o m s , the p a t i e n t was a d m i t t e d to our clinic w i t h p a i n and weakness in t h e right leg. On physical e x a m i n a t i o n wasting of b o t h legs, m u c h worse on the right side, was found, t t y p a e s t h e s i a to pinprick on the right side in the L 5 and S l distributions was noted. The right Achilles and p l a n t a r reflexes were sere-

Figs. 1 a and b. P o s t e r o a n t e r i o r and lateral views of w a t e r soluble m y e l o g r a m (Dimer-X), d e m o n s t r a t i n g c o m p l e t e block at the L 4/L 5 interspace. F u r t h e r partial defect at L 3/L 4 interspace rely depressed. The Las@gue test was strongly positive on the right side. X - r a y films d e m o n s t r a t e d t h e presence of arthrosis d e f o r m a n s of t h e l u m b a r spine, w i t h p r o m i n e n t bar formation. On S e p t e m b e r 9, 1974 w a t e r soluble m y e l o g r a p h y was performed, and this r e v e a l e d a complete block at the L 4/L 5 level associated w i t h a partial defect at the L 3/L 4 interspace w i t h o u t a n y evidence of serpentine defects (see Fig. 1). I t was concluded t h a t these defects were caused b y multiple disc lesions, w i t h a h e r n i a t e d l u m b a r disc at the L 4/L 5 level. On S e p t e m b e r 25, 1974 L 4/L 5 l a m i n e c t o m y was carried out. The lam i n a e were thicker t h a n n o r m a l and resembled white ivory. N o disc protrusions were found. The d u r a was tense and n o t pulsating. The l a m i n e c t o m y

tCedundant Nerve I~oots of the Cauda Equina

313

was then extended to the L 3 level where the spinal canal appeared narrower than usual. Once the dural sac was incised three nerve roots herniated through the opening. Significant araehnoiditis was noted round them, and their lengths were about 4: em greater than those of the other, normal, nerve roots of the cauda (see Fig. 2). The redundant nerve roots were freed from

Fig. 2. Operative photograph showing the redundant nerve roots freed from araehnoid adhesions araehnoid adhesions, and the dura was sutured. The postoperative course was uneventful. The patient was examined 4 and l0 months after surgery, and was found s y m p t o m free and able to work. Only the right Achilles reflex still remained depressed.

Comment I n T a b l e 1, 12 r e p o r t e d eases of r e d u n d a n t nerve roots in t h e e a u d a equina are listed. D e t a i l e d d a t a on t h r e e of t h e m are incomplete. E l e v e n p a t i e n t s u n d e r w e n t surgery, while one was tel~tatively d i a g n o s e d w i t h t h e a i d of m y e l o g r a p h y (Ehni et al. 1970). Nine o u t of t h e t e n p a t i e n t s on w h o m d a t a were a v a i l a b l e were male. The ages r a n g e d from 40 to 63 y e a r s w i t h no p r e p o n d e r a n c e in a n y one decade. The s y m p t o m a t o logy was u s u a l l y c h a r a c t e r i z e d b y low b a c k pain, m o t o r i n v o l v e m e n t , a n d sensory changes. I n two p a t i e n t s s p h i n c t e r disorders occurred. The o n l y a s y m p t o m a t i e ease, r e p o r t e d b y E h n i et al. (1970), was accid e n t a l l y d i a g n o s e d durillg positive c o n t r a s t m y e l o g r a p h y for s p o n d y lotic eervicM m y e l o p a t h y a n d r a d i c u l o p a t h y . P l a i n X - r a y films of t h e l u m b a r spine d e m o n s t r a t e d t h e f r e q u e n t

47

55

M

/Y[

5. Shut a n d Groff (1968)

6. L o m b a r d i (1969)

47

.

achondroplastie d w a r f ; low b a c k pain, progressiv e leg weakness, p a r a e s t h e s i a e in b o t h legs low b a c k pain, paraparosis, hypaes~hesia in L 3-S 2 distribution low b a c k pain, dorsiflexion deficit in t h e left food, paraesthesiae a n d dysaesthesiae in t h e r i g h t leg numbness and weakness of t h e r i g h t leg

.

radicular pain

--

63

-

Symptoms and physical signs

Age

M

.

-

Sex

4. Cressman and Pawl (1968)

2. i a n r a e ~ s (1959) 3. de L a n g e (1967)

1. Verbiest (1953) ~

R e p o r t e d cases I

.

.

--

--

L 4/L 5 interspace narrowing

spinal canal narrowing

---

Plain X-ray changes

Table I

complete block at L 3/L 4

complete block at L 4/L 5, serp e n t i n e defects a t L 3/L 4 complete b l o c k at L 3

complete block at L 3

.

complete b l o c k at L 4

Myelographic findings

A - V mMformarion

A-V malform a r i o n or vascular tumour

A-V malform a r i o n or vascular tumour

--

disc lesion (?)

Preoperative diagnosis

3

3

1

several

1

1

N e r v e roots involved

good recovery (4 rues postop.)

good recovery

good recovow (2 mos postop.)

good recovery (3 rues postop.)

total recovery

l~esult a n d fellow-up

~

M

12. Present case

61

61

40

50

58

cervical myelopathy and radiculopathy weakness and hypaesthesiae in the right leg weakness in both legs, hypaesthesiae in L 3/L 5 distribution bilaterally achondroplastie dwarf right sciatiea, weakness in both legs

low back pain, diffuse bilateral leg pain

arthrosis deformans of the lurebar spine

L 3/L 4 and L 4/L 5 interspace narrowings

L 1/L 2 interspac~ narrowing

lumbar spondylosis

complete block at L 4/L 5, partial block at L 3/L 4

serpentine defects at L 2/L 3

n a/L 4,

complete block at

L2

partial block at L 2/L 3 with serpentine defects partial block at L 4/L 5 complete block at

disc lesions

A - V malformation

r ed u n d an t nerve roots

A - V malformation

1 Some cases with partial or inadequate findings. The table refers to available data. 2 Quoted by Hanraets, 1959. The authors were n o t able to review this congress report. 3 Quoted by Sorensen a nd Wirthlin, 1975. Personal communication.

M

11. Gardner (1975) 8

M

9. Gulati and R o u t (1973)

M

M

8. Ehni et al. (1970)

10. Sorensen and Wirthlin ( 1975)

M

7. F o x (1969)

not verified

several

good recovery (10 rues postop.)

good recovery (3 ~ yrs postop.) mild recovery

o

o~

9

316

A. Pau and S. Turtas:

occurrence of degenerative bone changes. I n some cases, narrowing of disc space in the lumbar spine led to the initial erroneous diagnosis of a disc lesion. All patients were subjected to water soluble or pantopaque myelography. Complete or partial spinal block was recorded in all cases. The occasional presence of irregular large worm like channels in the myelographic picture led to a preoperative diagnosis of vascular anomaly or vascular tumour (Cressman and Pawl 1968, Shut and Groff 1968). Eleetromyography showed abnormalities in those patients on whom it was performed. Angiography was occasionally carried out, but no characteristic vascular patterns were found. Decompressive laminectomy was carried out in all the patients who were submitted to surgery. When a shallow or narrow spinal canal was revealed b y radiography or during surgery (de Lange 1967, Cressman and Pawl 1968), the dura was left open to provide additional decompression. Closure of the dura with a silastic dural graft seemed appropriate in two cases (Fox 1969, Sorensen and Wirthlin 1975). Arachnoiditis in association with redundant nerve roots occurred inconstantly. I n four cases there was one redundant root. In another four cases three roots were involved. I n two further cases several roots appeared redundant. Surgery was always followed by partial or total recovery. Pathogenesis is still obscure. Two possible mechanisms, which could cause stretching of cauda equina roots, have been considered. Firstly, stretching of the nerve roots could be related to recurring vertebral stress in the presence of spondylotic changes (Ehni et al. 1970), but the rarity of the condition contrasts with the frequency of spondylotic changes, and it must be remembered t h a t some of the nerve roots were elongated for distances exceeding 10 era. Secondly, redundant nerve roots m a y be local manifestations of hypertrophic interstitial neurop a t h y (Shut and Groff 1968). However, the absence of a family history of this disease or of ataxia or of involvement of peripheral nerves in our patients is a pointer against this hypothesis. Association of both achondroplasia and redundant nerve roots has been noted out in two cases (de Lange 1967, Gardner quoted b y Sorensen and Wirthlin 1975). This is worth mentioning because it suggests a congenital anomaly which m a y or m a y not be associated with narrowing of the spinal canal.

References

Cressman, M. 1%., Pawl, R. P., Serpentine myelographic defect caused by a redundant nerve root. Case report. J. Neurosurg. 28 (1968), 391--393. Ehni, G., Moiel, 1%. H., Bragg, T. G., The "redundant" or "knotted" nerve root: a clue to spondylotie eauda equina radieulopathy. Case report. J. Neurosurg. 32 (1970), 252--254.

R e d u n d a n t Nerve Roots of the Cauda Equine,

317

Fox, G. L., R e d u n d a n t nerve roots in the eauda equine. Case report. J. Neurosurg. 30 (1969), 74~75. Gardner, W. J., quoted by Sorensen and Wirthlin, 1975. Personal communication. Gulati, D. R., Rout, D., Myelographie block caused by redundant lumbar nerve root. Case report. J. Neurosurg. 38 (1973), 504--505. Hanraets, P. R. M. J., The degenerative back, p. 199. Amsterdam, London, New York, Princeton: Elsevier. 1959. de Lange, S. A., Eine Anomalie der Cauda equine bei einer achondroplastisehen Frau. Aeta neuroehir. (Wien) 16 (1967), 114--121. Lombardi, V., R e d u n d a n t nerve root of the eauda equina: a case report. Neurology 19 (1969), 1223--1224. Shut, L., Groff, R. A., R e d u n d a n t nerve roots as a cause of complete myelographic block. Case report. J. Neurosurg. 28 (1968), 394--395. Sorensen, B . F . , Wirthlin, A . J . , R e d u n d a n t nerve roots of the cauda equine. Surg. Neurol. 3 (1975), 177--181. Verbiest, H., quoted by Hanraets, 1959. Authors' address: Dr. A. Pau and Dr. S. Turtas, Neurosurgical Clinic of the University, Ospedale Civile Nuovo, 1-07100 Sassari, Italy.

Aeta Neurochirurgica,Vol.33, Fasc. 3--4

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Redundant nerve roots of the cauda equina. A case report.

Aeta Neuroehirurgiea 33, 311--317 ( 1976 ) 9 by Springer-Verlag 1976 Neurosurgieal Clinic of the University of Sassari, Italy (Director: Prof. G. L...
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