TMJ Surgery required for correction of injury. TMJ and Whiplash Injuries

Like any other joint in the body, the TMJ can experience a hyper-extension or sprain injury.  Many times, this can occur undiagnosed in childhood during falls with direct blows to the jaw.  Problems can progress due to poor joint mechanics and issues with growth and development from that point forward.  Many times, TMJ injury will occur with any blow to the jaw.  It can also occur during rear end automobile collisions or part of a “whiplash” injury mechanism.

 Until 1989, there were no laboratory or crash testing studies which studied the phenomenon of the TMJ injury during a rapid flexion/extension injury to the neck, commonly known as “whiplash”.  Computer studies confirmed the phenomenon.  Unfortunately, most crash studies use mannequins in test studies with solid heads, and no movable jaw component.  This is a significant study flaw.

Energy thresholds and mechanisms of neck injury are now well known after whiplash.  Computer studies have shown that there is an acceleration forward of the condyle of the jaw during the whiplash sequence.  Violent mouth opening action can occur during the head extension component of whiplash injuries.  Mathmatical logarithms based on computer simulated studies predict that rear end collisions resulting in vehicle displacement of 20-25 mph create forces in the human TMJ that are 2-5 times that of physiologic function.

Clinically, a hyper-extension injury to the TMJ can cause internal rupture of a ligament structure known as the posterior ligament attachment to the capsule of the TMJ. It can also cause rupture or detachment of the disc/capsule to the lateral attachment of these structures to the condyle of the jaw.  Studies have shown that the amount of force required to cause detachment of these ligament attachments to the lateral portion of the condyle are roughly 10-15% of forces generated in the joint during chewing function.  The analogy is the athlete who severely injuries his knee and tears ligaments in the knee.  We have all seen that unfortunate event on TV.

Unfortunately, this injury can be subtle and diagnosis can be delayed.  Most patients and neurosurgeons/orthopedic surgeons/therapists managing the neck injury are pre-occupied with this injury, and rightly so.  Many patients complain of TMJ soreness or pain initially but it is the neck injury that is initially most impairing.  When patients begin to advance the diet over time and load the TMJ with chewing force, symptoms progress.  Unfortunately, it is not a universal standard of care to carefully examine and record the TMJ sprain or hyper-extension injury in initial patient evaluation.  One arthoroscopic TMJ surgery/exploration study has been performed in Europe which documented blood in TM joints and injury to ligament tissues as noted above.  Arthroscopic examination was performed within 1-2 days of whiplash injury.

When sever enough, injuries that do not heal themselves will progress due to the physics and bio-mechanics of joint movement when under required function loads (chewing force).  Diagnosis is key and must be confirmed with MRI examination.

Sagittal and Coronal MRI scan of patient who had been rear ended by another vehicle traveling at estimates of 15 mph at impact.  Lateral or sagittal views appear normal.  Coronal scans show signal of high intensity at lateral pole of condyle which represents a tear or rupture of the capsule to the lateral most aspect of the mandibular condyle.  Patient required TMJ surgery to repair the ruptured disc/capsule.  Joint was very unstable and painful when patient attempted to chew food and mouth opening was compromised.

BIBLIOGRAPHY

1. Roydhouse RH. “Whiplash and TMJ dysfunction”. Lancet 1:1394

2. Lader E: Cervical trauma as a factor in the development of TMJ dysfunction and facial pain. Jnl Craniomand Pract. 1:85, 1983.

3. Weinberth S, PaPointe H: Cervical extension-flexion injury (whiplash) and internal derangement of the TMJ. Jnl Oral Maxillofacial Surgery, 45:653-656, 1987.

4. Schneider K, Zernicke RF, Clark GL: Modeling of Jaw-head-neck dynamics during whiplash. J Dent Res 68(9): 1360-1365, 1989.

5. Croft AC: Cervical acceleration/deceleration trauma: a reappraisal of physical and biomechanical events. Jnl of Neuromusc. Syst. Vol 1, no. 2 pp. 45-51, 1993.

6. Ben Amor R, Carpentier P, Foucart JM, and Meunier A: “Anatomic and mechanical properties of the lateral disc attachment of the TMJ.” Jnl of Oral Maxillofacial Surgery 56: 1164-1167, 1998.

Tags: jaw joint, Jaw Pain, orthopedic surgery of jaw, tmj, TMJ Dentist, tmj disorder, TMJ Impingement, TMJ Injury, TMJ MRI, TMJ Surgery, TMJ Surgury, whiplash