The pattern of reflex recovery during spinal shock

Abstract

Study Design: A prospective descriptive study of the course of recovery of re¯exes following acute spinal cord injury (SCI). Objectives: The purpose of the study was to observe the pattern of re¯ex recovery following acute SCI in order to determine the prognostic signi®cance of re¯exes for ambulation and their relationship to spinal shock. Setting: A regional spinal cord injury center in Philadelphia, Pennsylvania, USA. Methods: Fifty subjects admitted consecutively over a 9 month period and on the day of injury were observed for the following re¯exes; bulbo-cavernosis (BC), delayed plantar response (DPR), cremasteric (CRM), ankle jerk (AJ), knee jerk (KJ), and normal plantar response for 5 ± 7 days a week and 6 ± 8 weeks duration. The 50 subjects were assessed for ambulation of 200 feet at time of discharge. MRI studies were reviewed on 13/28 complete (ASIA A) injuries. Results: Thirty-®ve subjects (28 ASIA A, 4 ASIA B, 3 ASIA C) had a DPR of 2 days or longer duration and these subjects were not ambulatory. The fourteen subjects (12 ASIA D and 2 ASIA C), who were ambulatory, either had no DPR (11/14) or had a DPR of only 1 days duration (3/14). One subject (ASIA B) was not ambulatory and had a DRP of 1 days duration. The DPR was the ®rst re¯ex to recover most often, followed by the BC, CRM in the ®rst few days and later followed by the deep tendon re¯exes (AJ & KJ) by 1 ± 2 weeks respectively. Less than 8% of subjects had no re¯exes on the day of injury and the re¯exes did not follow a caudal-rostral pattern of recovery. Conclusions: Prognosis for ambulation based on re¯exes early after SCI should not be linked to current descriptions of spinal shock. In fact, the view of spinal shock, based on the absence of re¯exes and the recovery of re¯exes in a caudal to rostral sequence, is of limited clinical utility and should be discarded. The evolution of re¯exes over several days following injury may be more relevant to prognosis than the use of the term spinal shock and the presence or absence of re¯exes on the day of injury.

Spinal shock revisited: a four-phase model

“…Following the appearance of the DPR, reflexes tend to return in the following sequence: bulbocavernosus (BC), cremasteric (CM), ankle jerk (AJ), Babinski sign, and knee jerk (KJ) ( Table 2). 7 The general pattern of recovery appears to be cutaneous (polysynaptic) reflexes before DTRs 7 rather than the caudal to cranial recovery proposed by Guttmann. 13 A new paradigm of spinal shock Previous descriptions of spinal shock require clarification for two reasons: (1) not all reflexes are uniformly abolished in humans, since some reflexes are often only depressed and can be elicited, and (2) spinal shock does not resolve abruptly but rather in a series of phases extending over days to weeks to months.…”

“…3 Since Hall's description 150 years ago, the implications and physiologic basis of spinal shock have been a source of ongoing debate and discussion. Several recent editorial comments 4,5 and articles 6,7 have criticized the term as being a source of confusion. Atkinson and Atkinson 6 point out that hypovolemic shock and spinal shock are frequently confused and this can lead to serious mismanagement 4 as the former requires fluid replacement and the latter vasopressors.…”

“…Others 11,12 state that it ends with the recovery of deep tendon reflexes (DTRs), which in complete human SCI may not reappear for several weeks. 7 Still other clinicians define the resolution of spinal shock as the return of reflexive detrusor function months following injury. Sherrington 1,8 felt that 'noci-ceptive' (polysynaptic) reflexes were depressed for a shorter duration than monosynaptic DTRs.…”

“…7 The persistence of the DPR beyond 7 days is associated with severe SCI and a poor prognosis for ambulation. Following the appearance of the DPR, reflexes tend to return in the following sequence: bulbocavernosus (BC), cremasteric (CM), ankle jerk (AJ), Babinski sign, and knee jerk (KJ) ( Table 2).…”

A systematic review of the evidence supporting a role for vasopressor support in acute SCI

“…25 At that time, reflex hyperactivity begins manifesting as muscle spasms and elevation of blood pressure. 14,26 Furthermore, Ko and coworkers 27,28 specified that the time of return of deep tendon reflexes after SCI is within the first couple of weeks after injury with the delayed plantar reflex being the first followed by the bulbocavernous and cremasteric reflex. However, no established connection between spinal shock and neurogenic shock does exist.…”