British Journal of Neurosurgery (1990) 4,205-210
ORIGINAL ARTICLE
Br J Neurosurg Downloaded from informahealthcare.com by University of Newcastle on 01/07/15 For personal use only.
Prognosis for recovery of bladder function following lumbar central disc prolapse JOHN R. W.GLEAVE & ROBERT MACFARLANE
Department of Neurological Surgery, Addenbrooke’s Hospital, Cambridge, United Kingdom
Abstract From a retrospective review of 932 patients undergoing surgery for prolapsed lumbar intervertebral disc a group of 33 cases with acute urinary retention was studied. There was no identifiable factor which predisposed this subgroup of patients to cauda equina compression. The mean duration of bladder paralysis prior to operation was 3.6 days. Ultimately almost 79% of patients claimed full recovery of bladder function, but only 22% were left without sensory deficit in the limbs or perineum. There was no correlation between recovery and the duration of bladder paralysis before surgery, except in three patients in whom there was no sciatica and where the correct diagnosis was delayed for many days. Retention developing less than 48 h after an acute prolapse was associated with a poorer prognosis. Despite claims that bladder paralysis should be treated with the same urgency as an extradural haematoma, there is no evidence in this study or in the literature to support the view that emergency surgery has any bearing upon the degree of clinical recovery. The exception may be if decompression can be undertaken within 6 h, the time estimated for axonal ischaemia to become irreversible. This should not however engender complacency in the management of this condition, which still requires prompt treatment. Whilst any apparent delay to surgery may have medicolegal implications should the patient fail to recover completely, in the majority of cases the die is cast at the time the prolapse occurs.
Key words: Lumbar prolapsed disc, cauda equina compression, urinary incontinence.
Introduction Classical surgical teaching dictates that cauda equina compression following prolapsed intervertebral disc should be treated as a surgical emergency. An incomplete recovery may be linked by the patient to a perceived delay in diagnosis or treatment, and litigation may ensue. In an attempt to ascertain the relationship between the speed of decompression and prognosis, a clinical study of the treatment of the condition has been undertaken, and the literature reviewed.
Patients and method The case records of consecutive patients un-
dergoing lumbar disc surgery in the Neurosurgical Unit at Addenbrooke’s Hospital, Cambridge between 1966 and 1988 were reviewed retrospectively. During that period 1,03 1 prolapsed lumbar intervertebral discs were excised from 932 patients. The mean age at surgery was 40.6 years (range 16-77 years). Males were affected in 57.3% of cases. The most commonly affected interspaces were L4/5 (50.7%), and L5/S1 (45.5%). The disc was protruding centrally in 196 cases (19% of disc prolapses). Cauda equina compression developed in 29% of this group. Of these, 23 patients complained of urinary difficulty, and a further 33 (3.2% of all discs) had urinary retention with overflow incontinence. This
205
Br J Neurosurg Downloaded from informahealthcare.com by University of Newcastle on 01/07/15 For personal use only.
206
John R. W. Gleave & Robert Macfarlane
latter group has been studied in greater prolapse was necessary in 5 cases. The mean time to surgery in the 3 patients without pain detail. was 29 days (range 17-40 days), and in the The 33 cases of urinary retention occurred in 32 patients. One 29-year-old male presented remaining 30 it was 3.6 days (range 8 h-14 with retention from an acute central disc at days). L5/S1 from which he made a complete recovery. Four months later he presented with identical symptoms, on this occasion from a Results prolapse at L4/5. Only patients completely unable to void, or who had bladder enlarge- The outcome in the 33 patients with urinary ment with dribbling incontinence were in- retention was classified as excellent if full cluded. The average age of the group was 41.2 bladder control was regained within six weeks, years (range 23-67 years). A history of trauma good if recovery was ultimately full but was given by 5 patients, and a further 5 had delayed, fair if the patient had voluntary previously undergone lumbar disc surgery, 2 at control but suffered from stress incontinence or lack of urinary sensation, and poor if they the same level. Patients were divided into two groups. remained incontinent. Results are given in Group I consisted of 20 patients in whom the Tables I and 11. The difference between mean onset of symptoms was followed within 48 h by delay to surgery and outcome in the groups was the development of urinary retention. Group not statistically significant. Full bladder control was claimed ultimately I1 contained 13 patients with a relentlessly progressive history of sciatica, ultimately cul- by 26 of the 33 patients (78.8%). Recovery minating in bladder paralysis. The prolapse took up to two years in some cases. Full motor occurred at L3/4 in 1 case, at L4/5 in 17 cases, recovery of the limbs occurred in 14 of the 21 and at L5/S1 in 15 cases. Sciatica was present patients affected preoperatively. Only 7 pain 30 cases, and was unilateral in 20, bilateral tients (22%) were left without residual saddle in 10. Limb weakness was bilateral in 11 or limb sensory changes. There was no correlapatients and unilateral in 10. Sensory loss was tion between the return of bladder function presented in all but 2 and was confined to the and the recovery of saddle anaesthesia, nor did limb in 7 and involved the saddle area or the presence of a complete myelographic block perineum in 24. The diagnosis was confirmed signify a worse prognosis. Insufficient data was by myelography in 28 patients. There was a available for meaningful assessment of persiscomplete myelographic block in 21 patients. tent sexual dysfunction. Of the 3 patients in The remainder were investigated by computer- whom retention was not accompanied by ized axial tomography. All patients were sciatica, 1 ultimately achieved a good recovery, treated surgically, 29 by laminectomy and 4 by 1 was fair, and the third patient remained fenestration. Transthecal removal of the disc incontinent. TABLE I. Urinary recovery in 33 patients with incontinence from acute central lumbar disc prolapse Group
I
I1
Mean delay to surgery*
3.3 days 4.1 days
Outcomet Poor
Total
3
3
20
1
0
13
Excellent
Good
Fair
10 6
4 6
*The three patients with a long delay to surgery owing to the absence of pain are not included in the mean time to surgery because of the skew they induce in the figures. tSee text for definitions.
Recovey of bladder function after central disc prolapse
compared to those with an insidiously progressive lesion. The only substantial delay occurred in patients who did not have sciatica. Outcome Mean delay to surgery Although genital pain is said to accompany the onset of retention in this group,3 it was not Excellent (n=16) 3.3 days (range 8 h-14 days) Good ( n = 9 ) 4.1 days (range 1-7 days) reported by any of our cases. On occasions Fair ( n = 3 ) 2.9 days (range 12 h-5 days) sciatica may be abolished at the onset of Poor ( n = 2 ) 5.0 days (range 2-8 days) ~etention.~-~ As in other studies, motor and urinary function recovered significantly better than Of the 23 patients with incomplete bladder sensation. Unlike Scott: we did not find that involvement none was rendered incontinent by persisting sacral anaesthesia was invariably surgery, and only 2 complained of residual accompanied by deranged bladder function, urinary or sexual difficulty. nor is this the experience of others.1° The difference between motor and sensory recovery probably occurs because compression Discussion of sensory fibres is proximal to the dorsal root The incidence of lumbar disc prolapse result- ganglion." This does not however explain why ing in bladder paralysis in this series was 3.2%. micturition should recover well, since this This is undoubtedly an overestimate of the relies upon an intact sacral reflex arc. The frequency of this condition. A significant reason is likely to be that questioning of the number of patients with disc prolapse are patient provides an over-optimistic account of treated conservatively, and whereas almost all bladder function following cauda equina comcases of cauda equina compression in this pression. A patient who can pass urine volunregion are referred for neurosurgical treat- tarily and hold it at will may claim full ment, onhopaedic surgeons will often operate recovery, yet urodynamic studies can show .~ emptying upon uncomplicated disc prolapse. Other complete detrusor f a i l ~ r e Bladder series report the incidence to be between is usually complete despite detrusor damage.I2 Micturition in these patients is performed by 2-6%.lW4 There does not appear to be a subgroup of straining, and stress incontinence is prevented patients with lumbar disc disease particularly by regular voiding. Patients may be unaware at risk of cauda equina compression. The that they do this.g In a long-term follow-up of frequency of the condition amongst central 16 patients with cauda equina syndrome Aho et disc protrusions is relatively low. In a series of al. found that 50% of patients with an atonic 243 central and centrolateral disc prolapses bladder had either minimal urinary difficulties ~ of our Fager noted that 72% of patients had either a or claimed normal f ~ n c t i 0 n . l Few complete or almost complete myelographic patients were studied urodynamically. Despite block, yet only 15 patients (6%) had urinary this, we believe that patient satisfaction is a di~turbance.~ This may be due to the triangular valid assessment of outcome since it is, after cross-section of the lumbar canal, which pro- all, the ultimate evaluation of treatment. The vides a recess for the centrally-placed nerve time taken for bladder recovery to occur is roots6 In addition, studies based upon Young's variable. Whilst Robinson concluded that if modulus suggest that centrally-placed roots are full control was to be regained it usually did so subject to less linear strain than peripherally within three months," Jennett suggests that repair of nervous tissue may take several placed elements.6 Our patients were classified into two groups years.' The relationship between the onset of cauda as described by S h e ~ h a r d .Like ~ others: we found a slightly shorter mean time to surgery equina paralysis and surgery, and its effect on in patients with an acute onset of symptoms recovery, is a fascinating aspect of this condiTABLE 11. Relationship between mean delay to surgery and outcome in 30 patients with retention following sciatica
Br J Neurosurg Downloaded from informahealthcare.com by University of Newcastle on 01/07/15 For personal use only.
207
Br J Neurosurg Downloaded from informahealthcare.com by University of Newcastle on 01/07/15 For personal use only.
208
John R. W. Gleave G, Robert Macfariane
tion. Presumably the pathologic factors are upon late even appear to do rather better.* We pressure and ischaemia. Lewis14 suggested that believe that the major determinant of prognosis 12 h was the critical time for ischaemic damage is the rapidity with which compression develof a peripheral nerve to become permanent, ops. Just as patients with rapidly progressing but later work has suggested that the time may spinal cord compression are less likely to make be less than 6 h.Is It is common orthopaedic a full recovery than those with an insidious experience working with tourniquets that neu- onset: so too are those patients in group I who rological deficit can develop after as short a rapidly develop neurological deficit following time as 2-3 h. All this work relates to their disc prolapse. The timing of surgery peripheral nerves, and there is no information appears to be relatively unimportant because it available on the effects of ischaemia on nerve is almost impossible to transfer the patient, roots. It is possible that they are more sensitive investigate the cause, and relieve the compresboth to pressure and ischaemia than the sion within the 6 h it takes for neural ischaemia peripheral nerve with its epineurium, perineu- to become irreversible. Jennett has suggested that patients with a long delay to surgery rium, and vasa nervorum. The significance of urinary difficulty, bi- (several weeks) may fare badly because of the lateral sciatica, and saddle sensory changes development of arachnoidal adhesions,' but in lumbar disc prolapse are well known to this is unsubstantiated. clinicians. Yet unless the bladder is almost Any perceived delay to surgery may have full when the compression occurs, and important medicolegal implications should the because the retention itself is almost invari- patient fail to recover fully. This is comably painless, it is likely to be several hours pounded by the dogmatic views that have been before the diagnosis is made. Of 195 cases expressed regarding the urgency with which the should be treated. There is no * ~ ' ~ ~ ~ ~ condition ~~~ reviewed in the l i t e r a t ~ r e , ' - ~ ~ including our own patients, it appears that in evidence to support the view that emergency only four instances (2%) was surgery under- surgery influences the degree of recovery. We taken within 6 h.2Jo Our mean time to believe that the die is cast at the time the surgery of 3.6 days is similar to that of other prolapse occurs. Nevertheless the disc prolapse ~eries.~.".'~Many authors advocate emer- should be removed at the earliest opportunity, gency surgery for this even both from the point of view of patient morale likening the urgency to that of an extradural and comfort, and because any delay in treathaematoma.) Others are less aggressive, sug- ment can only worsen neurological recovery. gesting that the prognosis is poorer only if However, it is questionable whether it is always compression is not relieved within two appropriate to treat such cases with the same weeks.I6 Yet despite these various claims urgency as an extradural haematoma as sugthere is no evidence in the literature to gested by O'Laoire et ui.) Emergency surgery is support the view that urgent decompression often delegated to relatively inexperienced has any bearing upon clinical outcome. surgeons. This operation can be considerably The possible exception is the degree of more difficult than routine lumbar disc surgery. detrusor damage, as assessed urodynami- Bleeding from engorged epidural veins may callyY1'although it is uncertain whether this a be brisk, and it is occasionally necessary to reflection of neurogenic damage at a spinal remove large sequestrated disc fragments translevel, or the result of prolonged bladder thecally. Urgent surgery for patients with distension. Bladder musculature does not incomplete cauda equina compression is essenbecome flaccid as a result of denervation tial because it may prevent complete paralysis.' alone.' Avoidance of overdistension of the bladder in That early operation does not improve the pre- and postoperative period may reduce prognosis appears to defy surgical logic. In the risk of permanent detrusor damage due to some series, paradoxically, patients operated myogenic d e c o r n p e n ~ a t i o n . ~ ~ ~ ' ~
Recovery of bladder junction after central disc prolapse Conclusion
Br J Neurosurg Downloaded from informahealthcare.com by University of Newcastle on 01/07/15 For personal use only.
This article is not intended to encourage a laissez faire attitude to the treatment of cauda equina compression, but to suggest that the extent of urinary recovery may depend more upon the nature of the disc prolapse than the speed at which the nerve roots are decompressed.
Address for correspondence: Mr R. Macfarlane, FRCS, Department of Neurological Surgery, Addenbrooke’s Hospital, Hill’s Road, Cambridge CB2 2QQ, UK. References 1 Jennett WB. A study of 25 cases of compression of the cauda equina by prolapsed intervertebral discs. J Neurol Neurosurg Psychiat 1956; 19:109-16. 2 Kostuik JP, Harrington I, Alexander D, Rand W, Evans D. Cauda equina syndrome and lumbar disc herniation. J Bone Jt Surg 1986; 68A:386-91. 3 O’Laoire SA, Crockard HA, Thomas DG. Prognosis for sphincter recovery after operation for cauda equina compression owing to lumbar disc prolapse. Br Med J 1981; 282: 1852-4. 4 Robinson RG. Massive protrusions of lumbar disks. Br J Surg 1965; 52858-65. 5 Fager CA. Ruptured median and paramedian lumbar disk. A review of 243 cases. Surg Neurol 1985; 23:309-23.
209
6 Lafuente DJ, Andrew J, Joy A. Sacral sparing with cauda equina compression from central lumbar intervertebral disc prolapse. J Neurol Neurosurg Psychiat 1985; 48:579-81. 7 Shephard RH. Diagnosis and prognosis of cauda equina syndrome produced by protrusion of lumbar disk. Br Med J 1959; 21434-9. 8 Fairburn B, Stewart JM. Lumbar disc protrusion as a surgical emergency. Lancet 1955; ii:319-21. 9 Scott PJ. Bladder paralysis in cauda equina lesions from disc prolapse. J Bone Jt Surg 1965; 47B:224-35. 10 Hellstrom P, Kortelainen P, Kontturi M. Late urodynamic findings after surgery for cauda equina syndrome caused by a prolapsed lumbar intervertebral disk. J Urol 1986; 135:308-12. 11 O’Connell JEA. The indications for and results of the excision of lumbar intervertebral disc protrusions; a review of 500 cases. Ann R Coll Surg Engl 1950; 6:403-12. 12 McGuire EJ. Lower motor neuron lesions. In: Kaufmann JJ, ed. Current Urologic Therapy. Philadelphia: WB Saunders Co, 1980; sect. 4, 240-3. 13 Aho AJ, Auranen A, Personen K. Analysis of cauda equina symptoms in patients with lumbar disc prolapse. Acta Chir Scand 1969; 135413-20. 14 Lewis T. Vascular Disorders of the Limb, 2nd edn. London: Macmillan, 1946; 22. 15 Dyck PJ, Thomas PK, Lambert EH, Bunge R. eds. Peripheral Neuropathy, 2nd edn, Philadelphia: WB Saunders Co, 1984; 63-4. 16 Tay EC, Chacha PB. Midline prolapse of a lumbar intervertebral disc with compression of the cauda equina. J Bone Jt Surg 1979; 61B:43-6. 17 Nielsen B, de Nully M, Schmidt K, lversen Hansen R. A urodynamic study of cauda equina syndrome due to lumbar disc herniation. Urol Int 1980; 35:167-70.
ORIGINAL ARTICLE
Br J Neurosurg Downloaded from informahealthcare.com by University of Newcastle on 01/07/15 For personal use only.
Prognosis for recovery of bladder function following lumbar central disc prolapse JOHN R. W.GLEAVE & ROBERT MACFARLANE
Department of Neurological Surgery, Addenbrooke’s Hospital, Cambridge, United Kingdom
Abstract From a retrospective review of 932 patients undergoing surgery for prolapsed lumbar intervertebral disc a group of 33 cases with acute urinary retention was studied. There was no identifiable factor which predisposed this subgroup of patients to cauda equina compression. The mean duration of bladder paralysis prior to operation was 3.6 days. Ultimately almost 79% of patients claimed full recovery of bladder function, but only 22% were left without sensory deficit in the limbs or perineum. There was no correlation between recovery and the duration of bladder paralysis before surgery, except in three patients in whom there was no sciatica and where the correct diagnosis was delayed for many days. Retention developing less than 48 h after an acute prolapse was associated with a poorer prognosis. Despite claims that bladder paralysis should be treated with the same urgency as an extradural haematoma, there is no evidence in this study or in the literature to support the view that emergency surgery has any bearing upon the degree of clinical recovery. The exception may be if decompression can be undertaken within 6 h, the time estimated for axonal ischaemia to become irreversible. This should not however engender complacency in the management of this condition, which still requires prompt treatment. Whilst any apparent delay to surgery may have medicolegal implications should the patient fail to recover completely, in the majority of cases the die is cast at the time the prolapse occurs.
Key words: Lumbar prolapsed disc, cauda equina compression, urinary incontinence.
Introduction Classical surgical teaching dictates that cauda equina compression following prolapsed intervertebral disc should be treated as a surgical emergency. An incomplete recovery may be linked by the patient to a perceived delay in diagnosis or treatment, and litigation may ensue. In an attempt to ascertain the relationship between the speed of decompression and prognosis, a clinical study of the treatment of the condition has been undertaken, and the literature reviewed.
Patients and method The case records of consecutive patients un-
dergoing lumbar disc surgery in the Neurosurgical Unit at Addenbrooke’s Hospital, Cambridge between 1966 and 1988 were reviewed retrospectively. During that period 1,03 1 prolapsed lumbar intervertebral discs were excised from 932 patients. The mean age at surgery was 40.6 years (range 16-77 years). Males were affected in 57.3% of cases. The most commonly affected interspaces were L4/5 (50.7%), and L5/S1 (45.5%). The disc was protruding centrally in 196 cases (19% of disc prolapses). Cauda equina compression developed in 29% of this group. Of these, 23 patients complained of urinary difficulty, and a further 33 (3.2% of all discs) had urinary retention with overflow incontinence. This
205
Br J Neurosurg Downloaded from informahealthcare.com by University of Newcastle on 01/07/15 For personal use only.
206
John R. W. Gleave & Robert Macfarlane
latter group has been studied in greater prolapse was necessary in 5 cases. The mean time to surgery in the 3 patients without pain detail. was 29 days (range 17-40 days), and in the The 33 cases of urinary retention occurred in 32 patients. One 29-year-old male presented remaining 30 it was 3.6 days (range 8 h-14 with retention from an acute central disc at days). L5/S1 from which he made a complete recovery. Four months later he presented with identical symptoms, on this occasion from a Results prolapse at L4/5. Only patients completely unable to void, or who had bladder enlarge- The outcome in the 33 patients with urinary ment with dribbling incontinence were in- retention was classified as excellent if full cluded. The average age of the group was 41.2 bladder control was regained within six weeks, years (range 23-67 years). A history of trauma good if recovery was ultimately full but was given by 5 patients, and a further 5 had delayed, fair if the patient had voluntary previously undergone lumbar disc surgery, 2 at control but suffered from stress incontinence or lack of urinary sensation, and poor if they the same level. Patients were divided into two groups. remained incontinent. Results are given in Group I consisted of 20 patients in whom the Tables I and 11. The difference between mean onset of symptoms was followed within 48 h by delay to surgery and outcome in the groups was the development of urinary retention. Group not statistically significant. Full bladder control was claimed ultimately I1 contained 13 patients with a relentlessly progressive history of sciatica, ultimately cul- by 26 of the 33 patients (78.8%). Recovery minating in bladder paralysis. The prolapse took up to two years in some cases. Full motor occurred at L3/4 in 1 case, at L4/5 in 17 cases, recovery of the limbs occurred in 14 of the 21 and at L5/S1 in 15 cases. Sciatica was present patients affected preoperatively. Only 7 pain 30 cases, and was unilateral in 20, bilateral tients (22%) were left without residual saddle in 10. Limb weakness was bilateral in 11 or limb sensory changes. There was no correlapatients and unilateral in 10. Sensory loss was tion between the return of bladder function presented in all but 2 and was confined to the and the recovery of saddle anaesthesia, nor did limb in 7 and involved the saddle area or the presence of a complete myelographic block perineum in 24. The diagnosis was confirmed signify a worse prognosis. Insufficient data was by myelography in 28 patients. There was a available for meaningful assessment of persiscomplete myelographic block in 21 patients. tent sexual dysfunction. Of the 3 patients in The remainder were investigated by computer- whom retention was not accompanied by ized axial tomography. All patients were sciatica, 1 ultimately achieved a good recovery, treated surgically, 29 by laminectomy and 4 by 1 was fair, and the third patient remained fenestration. Transthecal removal of the disc incontinent. TABLE I. Urinary recovery in 33 patients with incontinence from acute central lumbar disc prolapse Group
I
I1
Mean delay to surgery*
3.3 days 4.1 days
Outcomet Poor
Total
3
3
20
1
0
13
Excellent
Good
Fair
10 6
4 6
*The three patients with a long delay to surgery owing to the absence of pain are not included in the mean time to surgery because of the skew they induce in the figures. tSee text for definitions.
Recovey of bladder function after central disc prolapse
compared to those with an insidiously progressive lesion. The only substantial delay occurred in patients who did not have sciatica. Outcome Mean delay to surgery Although genital pain is said to accompany the onset of retention in this group,3 it was not Excellent (n=16) 3.3 days (range 8 h-14 days) Good ( n = 9 ) 4.1 days (range 1-7 days) reported by any of our cases. On occasions Fair ( n = 3 ) 2.9 days (range 12 h-5 days) sciatica may be abolished at the onset of Poor ( n = 2 ) 5.0 days (range 2-8 days) ~etention.~-~ As in other studies, motor and urinary function recovered significantly better than Of the 23 patients with incomplete bladder sensation. Unlike Scott: we did not find that involvement none was rendered incontinent by persisting sacral anaesthesia was invariably surgery, and only 2 complained of residual accompanied by deranged bladder function, urinary or sexual difficulty. nor is this the experience of others.1° The difference between motor and sensory recovery probably occurs because compression Discussion of sensory fibres is proximal to the dorsal root The incidence of lumbar disc prolapse result- ganglion." This does not however explain why ing in bladder paralysis in this series was 3.2%. micturition should recover well, since this This is undoubtedly an overestimate of the relies upon an intact sacral reflex arc. The frequency of this condition. A significant reason is likely to be that questioning of the number of patients with disc prolapse are patient provides an over-optimistic account of treated conservatively, and whereas almost all bladder function following cauda equina comcases of cauda equina compression in this pression. A patient who can pass urine volunregion are referred for neurosurgical treat- tarily and hold it at will may claim full ment, onhopaedic surgeons will often operate recovery, yet urodynamic studies can show .~ emptying upon uncomplicated disc prolapse. Other complete detrusor f a i l ~ r e Bladder series report the incidence to be between is usually complete despite detrusor damage.I2 Micturition in these patients is performed by 2-6%.lW4 There does not appear to be a subgroup of straining, and stress incontinence is prevented patients with lumbar disc disease particularly by regular voiding. Patients may be unaware at risk of cauda equina compression. The that they do this.g In a long-term follow-up of frequency of the condition amongst central 16 patients with cauda equina syndrome Aho et disc protrusions is relatively low. In a series of al. found that 50% of patients with an atonic 243 central and centrolateral disc prolapses bladder had either minimal urinary difficulties ~ of our Fager noted that 72% of patients had either a or claimed normal f ~ n c t i 0 n . l Few complete or almost complete myelographic patients were studied urodynamically. Despite block, yet only 15 patients (6%) had urinary this, we believe that patient satisfaction is a di~turbance.~ This may be due to the triangular valid assessment of outcome since it is, after cross-section of the lumbar canal, which pro- all, the ultimate evaluation of treatment. The vides a recess for the centrally-placed nerve time taken for bladder recovery to occur is roots6 In addition, studies based upon Young's variable. Whilst Robinson concluded that if modulus suggest that centrally-placed roots are full control was to be regained it usually did so subject to less linear strain than peripherally within three months," Jennett suggests that repair of nervous tissue may take several placed elements.6 Our patients were classified into two groups years.' The relationship between the onset of cauda as described by S h e ~ h a r d .Like ~ others: we found a slightly shorter mean time to surgery equina paralysis and surgery, and its effect on in patients with an acute onset of symptoms recovery, is a fascinating aspect of this condiTABLE 11. Relationship between mean delay to surgery and outcome in 30 patients with retention following sciatica
Br J Neurosurg Downloaded from informahealthcare.com by University of Newcastle on 01/07/15 For personal use only.
207
Br J Neurosurg Downloaded from informahealthcare.com by University of Newcastle on 01/07/15 For personal use only.
208
John R. W. Gleave G, Robert Macfariane
tion. Presumably the pathologic factors are upon late even appear to do rather better.* We pressure and ischaemia. Lewis14 suggested that believe that the major determinant of prognosis 12 h was the critical time for ischaemic damage is the rapidity with which compression develof a peripheral nerve to become permanent, ops. Just as patients with rapidly progressing but later work has suggested that the time may spinal cord compression are less likely to make be less than 6 h.Is It is common orthopaedic a full recovery than those with an insidious experience working with tourniquets that neu- onset: so too are those patients in group I who rological deficit can develop after as short a rapidly develop neurological deficit following time as 2-3 h. All this work relates to their disc prolapse. The timing of surgery peripheral nerves, and there is no information appears to be relatively unimportant because it available on the effects of ischaemia on nerve is almost impossible to transfer the patient, roots. It is possible that they are more sensitive investigate the cause, and relieve the compresboth to pressure and ischaemia than the sion within the 6 h it takes for neural ischaemia peripheral nerve with its epineurium, perineu- to become irreversible. Jennett has suggested that patients with a long delay to surgery rium, and vasa nervorum. The significance of urinary difficulty, bi- (several weeks) may fare badly because of the lateral sciatica, and saddle sensory changes development of arachnoidal adhesions,' but in lumbar disc prolapse are well known to this is unsubstantiated. clinicians. Yet unless the bladder is almost Any perceived delay to surgery may have full when the compression occurs, and important medicolegal implications should the because the retention itself is almost invari- patient fail to recover fully. This is comably painless, it is likely to be several hours pounded by the dogmatic views that have been before the diagnosis is made. Of 195 cases expressed regarding the urgency with which the should be treated. There is no * ~ ' ~ ~ ~ ~ condition ~~~ reviewed in the l i t e r a t ~ r e , ' - ~ ~ including our own patients, it appears that in evidence to support the view that emergency only four instances (2%) was surgery under- surgery influences the degree of recovery. We taken within 6 h.2Jo Our mean time to believe that the die is cast at the time the surgery of 3.6 days is similar to that of other prolapse occurs. Nevertheless the disc prolapse ~eries.~.".'~Many authors advocate emer- should be removed at the earliest opportunity, gency surgery for this even both from the point of view of patient morale likening the urgency to that of an extradural and comfort, and because any delay in treathaematoma.) Others are less aggressive, sug- ment can only worsen neurological recovery. gesting that the prognosis is poorer only if However, it is questionable whether it is always compression is not relieved within two appropriate to treat such cases with the same weeks.I6 Yet despite these various claims urgency as an extradural haematoma as sugthere is no evidence in the literature to gested by O'Laoire et ui.) Emergency surgery is support the view that urgent decompression often delegated to relatively inexperienced has any bearing upon clinical outcome. surgeons. This operation can be considerably The possible exception is the degree of more difficult than routine lumbar disc surgery. detrusor damage, as assessed urodynami- Bleeding from engorged epidural veins may callyY1'although it is uncertain whether this a be brisk, and it is occasionally necessary to reflection of neurogenic damage at a spinal remove large sequestrated disc fragments translevel, or the result of prolonged bladder thecally. Urgent surgery for patients with distension. Bladder musculature does not incomplete cauda equina compression is essenbecome flaccid as a result of denervation tial because it may prevent complete paralysis.' alone.' Avoidance of overdistension of the bladder in That early operation does not improve the pre- and postoperative period may reduce prognosis appears to defy surgical logic. In the risk of permanent detrusor damage due to some series, paradoxically, patients operated myogenic d e c o r n p e n ~ a t i o n . ~ ~ ~ ' ~
Recovery of bladder junction after central disc prolapse Conclusion
Br J Neurosurg Downloaded from informahealthcare.com by University of Newcastle on 01/07/15 For personal use only.
This article is not intended to encourage a laissez faire attitude to the treatment of cauda equina compression, but to suggest that the extent of urinary recovery may depend more upon the nature of the disc prolapse than the speed at which the nerve roots are decompressed.
Address for correspondence: Mr R. Macfarlane, FRCS, Department of Neurological Surgery, Addenbrooke’s Hospital, Hill’s Road, Cambridge CB2 2QQ, UK. References 1 Jennett WB. A study of 25 cases of compression of the cauda equina by prolapsed intervertebral discs. J Neurol Neurosurg Psychiat 1956; 19:109-16. 2 Kostuik JP, Harrington I, Alexander D, Rand W, Evans D. Cauda equina syndrome and lumbar disc herniation. J Bone Jt Surg 1986; 68A:386-91. 3 O’Laoire SA, Crockard HA, Thomas DG. Prognosis for sphincter recovery after operation for cauda equina compression owing to lumbar disc prolapse. Br Med J 1981; 282: 1852-4. 4 Robinson RG. Massive protrusions of lumbar disks. Br J Surg 1965; 52858-65. 5 Fager CA. Ruptured median and paramedian lumbar disk. A review of 243 cases. Surg Neurol 1985; 23:309-23.
209
6 Lafuente DJ, Andrew J, Joy A. Sacral sparing with cauda equina compression from central lumbar intervertebral disc prolapse. J Neurol Neurosurg Psychiat 1985; 48:579-81. 7 Shephard RH. Diagnosis and prognosis of cauda equina syndrome produced by protrusion of lumbar disk. Br Med J 1959; 21434-9. 8 Fairburn B, Stewart JM. Lumbar disc protrusion as a surgical emergency. Lancet 1955; ii:319-21. 9 Scott PJ. Bladder paralysis in cauda equina lesions from disc prolapse. J Bone Jt Surg 1965; 47B:224-35. 10 Hellstrom P, Kortelainen P, Kontturi M. Late urodynamic findings after surgery for cauda equina syndrome caused by a prolapsed lumbar intervertebral disk. J Urol 1986; 135:308-12. 11 O’Connell JEA. The indications for and results of the excision of lumbar intervertebral disc protrusions; a review of 500 cases. Ann R Coll Surg Engl 1950; 6:403-12. 12 McGuire EJ. Lower motor neuron lesions. In: Kaufmann JJ, ed. Current Urologic Therapy. Philadelphia: WB Saunders Co, 1980; sect. 4, 240-3. 13 Aho AJ, Auranen A, Personen K. Analysis of cauda equina symptoms in patients with lumbar disc prolapse. Acta Chir Scand 1969; 135413-20. 14 Lewis T. Vascular Disorders of the Limb, 2nd edn. London: Macmillan, 1946; 22. 15 Dyck PJ, Thomas PK, Lambert EH, Bunge R. eds. Peripheral Neuropathy, 2nd edn, Philadelphia: WB Saunders Co, 1984; 63-4. 16 Tay EC, Chacha PB. Midline prolapse of a lumbar intervertebral disc with compression of the cauda equina. J Bone Jt Surg 1979; 61B:43-6. 17 Nielsen B, de Nully M, Schmidt K, lversen Hansen R. A urodynamic study of cauda equina syndrome due to lumbar disc herniation. Urol Int 1980; 35:167-70.
