British Journal of Neurosurgery, December 2013; 27(6): 852 © 2013 The Neurosurgical Foundation ISSN: 0268-8697 print / ISSN 1360-046X online DOI: 10.3109/02688697.2013.854310
LETTER TO THE EDITOR
Cauda equina syndrome: Findings on perineal examination
Table I. Perineal sensation. Timing O/E
Pre-CESR (CESI) @ CESR
Number of patient assessments Unilateral hypoaesthesia Bilateral hypoaesthesia Unilateral or bilateral anaesthesia
There is limited data as to how the objective signs of cauda equina syndrome (CES) change as CES becomes progressively more severe. I previously reviewed a database of 40 patients with CES who were assessed for medicolegal purposes.1 I revisited that database to identify patients who had had examination of the perineum and/or rectal examination as part of their clinical assessment. Patients were classified as having an incomplete cauda equina syndrome (CESI) or a cauda equina syndrome with neurogenic retention of urine (CESR). CESI was defined as objective evidence of CES, for example impaired perianal sensation, with preserved control of the bladder. The point of CESR was taken as either the complete inability to pass urine with absent bladder sensation; absent bladder sensation, catheterised, with a large residual bladder volume or an insensate paralysed bladder with incontinence. Some patients were assessed prior to CESR (CESI); some were examined at the moment that CESR was recognised; others were examined following CESR; some had examination at more than one point in time. Perineal sensation was assessed as (i) unilateral hypoaesthesia, (ii) bilateral hypoaesthesia or (iii) unilateral/bilateral anaesthesia. Anal tone was assessed as being normal, impaired or absent. Some patients only had assessment of perineal sensation or anal tone; some had assessment of both. Some patients had sensory examination at one point in time, others were examined more than once. No patient had more than one rectal examination. Of the 40 cases that were previously published,1 28 had sufficient information recorded to permit this analysis. The 12 patients that could not be assessed included patients who had intraoperative damage to the CE, one case of very longstanding CES (months) and patients in whom there was inadequate documentation of findings on clinical examination. Not all patients had assessment of both sensation and anal tone. Some patients were examined at different points in time and therefore the number of observations is greater than the number of patients. Of the 28 patients, 27 had written evidence of perineal sensory examination; there were 33 observations in 28 patients. Of 28 patients, 25 had findings on rectal examination recorded. The results are set out below (Tables I and II). All 27 patients had objective impairment of perianal sensation. There was a trend for the sensory losses to be greater as patients moved from CESI to CESR and then more prolonged CESR. Anal tone was normal in 2 (8%) of 25
0–24 h post-CESR
⬎ 24 h Post-CESR
6
6
15
6
1
0
2
0
4
5
6
2
1
1
7
4
Six patients had perineal sensation assessed more than once.
Table II. Anal tone. Timing O/E Number of patient assessments Anal tone normal Anal tone reduced Anal tone absent
Pre-CESR (CESI)
@ CESR
0–24 h post-CESR
⬎ 24 h Post-CESR
3
5
11
6
1 2 0
1 4 0
0 8 3
0 1 5
No patient had more than one rectal examination.
patients in whom rectal examination was performed. Anal tone was normal in one of three patients in CESI and one of five patients at the moment of CESR. Impairment of anal tone was present in all patients assessed after CESR. Anal tone was never wholly absent in patients in CESI or at the moment of CESR, but was more likely to be wholly absent where the assessment occurred after CESR and particularly in patients with CESR ⬎ 24 h. These data are from a highly selected group of patients who were assessed for the purposes of preparing medicolegal reports. The evidence suggests progression of objective signs of CES from early incomplete CES (CESI) to patients who had been in CESR for ⬎ 24 h. It looks as if the moment of CESR (the moment at which the bladder becomes paralysed and insensate) is one moment upon a pathway to complete loss of CE function. Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. Nicholas V. Todd 180 Portland Road, Sandyford, Newcastle upon Tyne, UK
Reference 1. Todd NV. Causes and outcomes of cauda equina syndrome in medico-legal practice: a single neurosurgical experience of 40 consecutive cases. Br J Neurosurg 2011;25:503–8.
852
Copyright of British Journal of Neurosurgery is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
LETTER TO THE EDITOR
Cauda equina syndrome: Findings on perineal examination
Table I. Perineal sensation. Timing O/E
Pre-CESR (CESI) @ CESR
Number of patient assessments Unilateral hypoaesthesia Bilateral hypoaesthesia Unilateral or bilateral anaesthesia
There is limited data as to how the objective signs of cauda equina syndrome (CES) change as CES becomes progressively more severe. I previously reviewed a database of 40 patients with CES who were assessed for medicolegal purposes.1 I revisited that database to identify patients who had had examination of the perineum and/or rectal examination as part of their clinical assessment. Patients were classified as having an incomplete cauda equina syndrome (CESI) or a cauda equina syndrome with neurogenic retention of urine (CESR). CESI was defined as objective evidence of CES, for example impaired perianal sensation, with preserved control of the bladder. The point of CESR was taken as either the complete inability to pass urine with absent bladder sensation; absent bladder sensation, catheterised, with a large residual bladder volume or an insensate paralysed bladder with incontinence. Some patients were assessed prior to CESR (CESI); some were examined at the moment that CESR was recognised; others were examined following CESR; some had examination at more than one point in time. Perineal sensation was assessed as (i) unilateral hypoaesthesia, (ii) bilateral hypoaesthesia or (iii) unilateral/bilateral anaesthesia. Anal tone was assessed as being normal, impaired or absent. Some patients only had assessment of perineal sensation or anal tone; some had assessment of both. Some patients had sensory examination at one point in time, others were examined more than once. No patient had more than one rectal examination. Of the 40 cases that were previously published,1 28 had sufficient information recorded to permit this analysis. The 12 patients that could not be assessed included patients who had intraoperative damage to the CE, one case of very longstanding CES (months) and patients in whom there was inadequate documentation of findings on clinical examination. Not all patients had assessment of both sensation and anal tone. Some patients were examined at different points in time and therefore the number of observations is greater than the number of patients. Of the 28 patients, 27 had written evidence of perineal sensory examination; there were 33 observations in 28 patients. Of 28 patients, 25 had findings on rectal examination recorded. The results are set out below (Tables I and II). All 27 patients had objective impairment of perianal sensation. There was a trend for the sensory losses to be greater as patients moved from CESI to CESR and then more prolonged CESR. Anal tone was normal in 2 (8%) of 25
0–24 h post-CESR
⬎ 24 h Post-CESR
6
6
15
6
1
0
2
0
4
5
6
2
1
1
7
4
Six patients had perineal sensation assessed more than once.
Table II. Anal tone. Timing O/E Number of patient assessments Anal tone normal Anal tone reduced Anal tone absent
Pre-CESR (CESI)
@ CESR
0–24 h post-CESR
⬎ 24 h Post-CESR
3
5
11
6
1 2 0
1 4 0
0 8 3
0 1 5
No patient had more than one rectal examination.
patients in whom rectal examination was performed. Anal tone was normal in one of three patients in CESI and one of five patients at the moment of CESR. Impairment of anal tone was present in all patients assessed after CESR. Anal tone was never wholly absent in patients in CESI or at the moment of CESR, but was more likely to be wholly absent where the assessment occurred after CESR and particularly in patients with CESR ⬎ 24 h. These data are from a highly selected group of patients who were assessed for the purposes of preparing medicolegal reports. The evidence suggests progression of objective signs of CES from early incomplete CES (CESI) to patients who had been in CESR for ⬎ 24 h. It looks as if the moment of CESR (the moment at which the bladder becomes paralysed and insensate) is one moment upon a pathway to complete loss of CE function. Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. Nicholas V. Todd 180 Portland Road, Sandyford, Newcastle upon Tyne, UK
Reference 1. Todd NV. Causes and outcomes of cauda equina syndrome in medico-legal practice: a single neurosurgical experience of 40 consecutive cases. Br J Neurosurg 2011;25:503–8.
852
Copyright of British Journal of Neurosurgery is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
