Date: Sat, 24 May 1997 08:44:35 -0400 (EDT) Subject: Re: Whiplash injury and proprioceptive deficits Reply-To: LHBWeitz@aol.com There is now evidence that whiplash injury to the cervical spine results in decreased proprioceptive ability. This has implications both for rehab and treatment of such patients. Could it be that manipulation has a beneficial effect on restoration of proprioception due to the reflexive effects on the facet joint capsule mechano-receptors or on the neck muscles? Perhaps incorporating specific rehab protocals focussed on restoring proprioception would help break the tendency towards chronicity of complaints in these patients. Both of these propositions would be ripe grounds for future research. A recent study (1) reveals that patients who have had a whiplash injuries have difficulty reproducing specific head positions. Such position sense is largely controlled via the integration of proprioceptive sensations from the neck. These sensations are received from muscle spindles in the intersegmental and posterior neck muscles via gamma-motor neurons, from golgi tendon organs at musculotendinous junctions and also from joint capsule receptors. This study looked at 11 subjects with a history of whilash injury and 11 age-matched asymptomatic controls. A CROM was afixed to each subject's head and they were asked to repeat various rotation and side bending positions of the cervical spine. The whiplash patients had difficulty, whereas the asymptomatic controls did not. In addition, when the subjects were asked to assume a neutral position, most of the whiplash patients assumed a position other than (0,0,0). This means that whiplash patients had some degree of lateral tilt or rotation of their head when they perceived their head as being straight. "Individuals who have sustained a whiplash injury may have proprioceptive eficits that do not allow them accurately or reliably to calculate head position. This may be detrimental to their everyday function. Freeman et al demonstrated that coordination activities and proprioceptive retraining can have a positive effect on restoration of kinesthetic awareness after injury.(2) Rehabilitation after whiplash injury should focus not only on range of motion and strength but on postural awareness. The focus should include reestablishement of appropriate position sense. Exercise must incorporate relearning of motor skills based on a new, perhaps abnormal sensory input. Proprioceptive training of the cervical spine should be investigated as a treatment approach in these individuals."(1,p.867) In a letter in this same issue of Spine by Rutten HP, et al., discussed the findings of Hack et al(3) where the discovery of a connection between the rectus capitis posterior minor muscle and the dural sac between occipital bone and atlas was reported. (Hack's paper also discussed the concept that tightness or dysfunction of the RCPM muscle is a possible mechanism of headaches.) Rutten et al note that there are also fibrous strands referred to as "craniale durae matris spinalis fibrous strands" that also connect the dura to the posterior arches of atlas, as well as to C2 and C3. Therefore, while these strands may be stronger than the connections between the dura and RCPM, they are not connected by muscle. The RCPM may function as a mechanorepetive device and he notes that this muscle has been shown to contain a great number of muscle spindles.(4,5) He notes that this proprioceptive mechanism may fail in whiplash patients. Hack in another letter responds by noting that the RCPM muscle undergoes fatty degeneration in patients with whiplash-like symptoms and that this has been shown on MRI.(6) This is likely due to trauma to this muscle. ***In summary: Neck muscles and joints contain proprioceptive nerve receptors, esp. in certain muscles, such as the RCPM. These may be injured in whiplash injuries. Could prolonged postural stresses also damage such muscles and their receptors? Atrophy of such muscles could be monitored with MRI. Proprioceptive ability can be monitored by the ability of such patients to reproduce certain head positions. Proprioceptive ability should be considered and addressed in the evaluation of whiplash and other neck pain patients. Proprioceptive retraining should be included in the rehab of such patients. What would be the best methods of achieving such proprioceptive retraining? Would wobble board training, etc. help? Should head position training be repeatedly be performed as a training program? Does manipulation affect such proprioceptive loss? This would be a way of testing some of the hypotheses floating around (such as those of Seaman) of the affect of manipulation on the mechanoreceptors in the neck. Can manipulation help with prevention or rehab of such proprioceptive losses? Can patients achieve a "truer" neutral position of their head (closer to 0,0,0) after manipulation? Can manipulation affect the likelihood of such upper cervical muscles to undergo fatty degeneration as seen on MRI? These would all be good questions to address in future research. (1) Loudon JK, Ruhl M, Filed E. Ability to reproduce head position after whiplash injury. Spine. 1997; 22:865-868. (2) Freeman MAR, Dean MRE, Hanham IWF. The etiology and prevention of functional instability of the foot. J Bone Joint Surg (Am) 1965;47:678-85. (3) Hack GD, Koritzer RT, Robinson WL, et al. Anatomic relation between the rectus capitis posterior minor muscle and the dura mater. Spine. 1995;20:2484-6. (4) Bakker DA, Richmond FJR. Muscle spindle complexes in muscles around upper cervical vertebrae in the cat. J Neurophysiol. 1982;48:62-74. (5) Taylor JL, McCloskey. Proprioception in the neck. Exp Brain Res. 1988;70: 351-60. (6) Hallgren RC, Greenman PE, Rechtien JJ. Atrophy of suboccipital muscles in patients with chronic pain: A pilot study. JAOA. 1994; 94:1032-8. Ben Weitz, D.C., C.C.S.P. LHBWeitz@aol.com -------------------------- Date: Sat, 24 May 1997 08:54:54 -0500 From: "Noel A. Taylor" Subject: Re: Whiplash injury and proprioceptive deficits >In a letter in this same issue of Spine by Rutten HP, et al., discussed the >findings of Hack et al(3) where the discovery of a connection between the >rectus capitis posterior minor muscle and the dural sac between occipital >bone and atlas was reported. (Hack's paper also discussed the concept that >tightness or dysfunction of the RCPM muscle is a possible mechanism of >headaches.) > >Rutten et al note that there are also fibrous strands referred to as >"craniale durae matris spinalis fibrous strands" that also connect the dura >to the posterior arches of atlas, as well as to C2 and C3. Therefore, while >these strands may be stronger than the connections between the dura and RCPM, >they are not connected by muscle. The RCPM may function as a mechanorepetive >device and he notes that this muscle has been shown to contain a great number >of muscle spindles.(4,5) He notes that this proprioceptive mechanism may >fail in whiplash patients. Ben: Thank you for a most excellent and informative post. I was not aware of the RCPM/dural connection. I would like to add that I've viewed 3 disections done by Mark Pick, a Beverly Hills DC and SORSI's leading anatomist, in which the "craniale durae matris spinalis fibrous strands" were found to attach to the posterior arches and between them to the PLL _throughout the spinal column_, not just in the upper cervical spine. I do not know if Dr. Pick's findings have been published yet, but the presence of this connection in three consecutive disections is suggestive of general condition, not to mention ripe with implications for our profession. Do you know of any published studies on the histology of these strands, with reference to the presence or absence of actin or myosin? --Noel ------------------------- Date: Sat, 24 May 1997 20:53:07 -0400 (EDT) From: Ed Owens To: LHBWeitz@aol.com Subject: Re: Whiplash injury and proprioceptive deficits Ben, Nice review, thanks. I've read a couple of those papers, the Hack in particular, but I've never seen it all put together into a meaningful work. You should consider submitting for publication somewhere. Another useful research area would be coming up with a less expensive test, palpation maybe, to arrive at the RCPMinor atrophy noted on MRI by Hack. Did Hack correlate clinical findings, other than chronic neck pain, with such atrophy? Ed Owens Editor, Chiropractic Research Journal --------------------------