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Lhermitte's Sign Developing after IMRT for Head and Neck Cancer.

Lim DC, Gagnon PJ, Meranvil S, Kaurin D, Lipp L, Holland JM - Int J Otolaryngol (2010)

Bottom Line: Results.Conclusions.We propose an anterior spinal cord structure, the spinothalamic tract to be the target of IMRT-caused LS.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Medicine, Oregon Health & Science University, Mailcode KPV4, 3181 Southwest Sam Jackson Park Road, Portland, OR 97239-3098, USA.

ABSTRACT
Background. Lhermitte's sign (LS) is a benign form of myelopathy with neck flexion producing an unpleasant electric-shock sensation radiating down the extremities. Although rare, it can occur after head and neck radiotherapy. Results. We report a case of Lhermitte's developing after curative intensity-modulated radiotherapy (IMRT) for a patient with locoregionally advanced oropharyngeal cancer. IMRT delivers a conformal dose of radiation in head and neck cancer resulting in a gradient of radiation dose throughout the spinal cord. Using IMRT, more dose is delivered to the anterior spinal cord than the posterior cord. Conclusions. Lhermitte's sign can develop after IMRT for head and neck cancer. We propose an anterior spinal cord structure, the spinothalamic tract to be the target of IMRT-caused LS.

No MeSH data available.


Related in: MedlinePlus

Radiation dose distribution represented by radiation isodose lines through an axial plane of  the cervical spinal cord.  (a) Dose distribution with IMRT  and (b) dose distribution using a non-IMRT plan using opposed lateral beams.  The light blue line represents the 4800 cGy isodose line and the purple line represents the 4500 cGy isodose line.
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fig2: Radiation dose distribution represented by radiation isodose lines through an axial plane of the cervical spinal cord. (a) Dose distribution with IMRT and (b) dose distribution using a non-IMRT plan using opposed lateral beams. The light blue line represents the 4800 cGy isodose line and the purple line represents the 4500 cGy isodose line.

Mentions: Using IMRT, a much different radiation dose distribution is delivered to the spinal cord than with non-IMRT opposed lateral radiotherapy. Rather than a homogeneous dose distributed throughout the cord, there is a dose gradient with most of the radiation delivered anteriorly. Figure 2 compares the spinal cord dose distribution seen in our IMRT case with the same patient if he were treated via a non-IMRT opposed laterals technique. Butler et al. hypothesized that the dorsal columns served as the radiation target leading to LS [11]. Given the development of LS in our patient and the more anterior radiation dose distribution seen with IMRT, we suggest a more anterior spinal cord tract as the target for IMRT-caused LS. As first mentioned by Jones, we hypothesize that irradiation of the spinothalamic tract, which recognizes simple touch, pain, and temperature, is the cause of LS for our patient (Figure 3).


Lhermitte's Sign Developing after IMRT for Head and Neck Cancer.

Lim DC, Gagnon PJ, Meranvil S, Kaurin D, Lipp L, Holland JM - Int J Otolaryngol (2010)

Radiation dose distribution represented by radiation isodose lines through an axial plane of  the cervical spinal cord.  (a) Dose distribution with IMRT  and (b) dose distribution using a non-IMRT plan using opposed lateral beams.  The light blue line represents the 4800 cGy isodose line and the purple line represents the 4500 cGy isodose line.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2902147&req=5

fig2: Radiation dose distribution represented by radiation isodose lines through an axial plane of the cervical spinal cord. (a) Dose distribution with IMRT and (b) dose distribution using a non-IMRT plan using opposed lateral beams. The light blue line represents the 4800 cGy isodose line and the purple line represents the 4500 cGy isodose line.
Mentions: Using IMRT, a much different radiation dose distribution is delivered to the spinal cord than with non-IMRT opposed lateral radiotherapy. Rather than a homogeneous dose distributed throughout the cord, there is a dose gradient with most of the radiation delivered anteriorly. Figure 2 compares the spinal cord dose distribution seen in our IMRT case with the same patient if he were treated via a non-IMRT opposed laterals technique. Butler et al. hypothesized that the dorsal columns served as the radiation target leading to LS [11]. Given the development of LS in our patient and the more anterior radiation dose distribution seen with IMRT, we suggest a more anterior spinal cord tract as the target for IMRT-caused LS. As first mentioned by Jones, we hypothesize that irradiation of the spinothalamic tract, which recognizes simple touch, pain, and temperature, is the cause of LS for our patient (Figure 3).

Bottom Line: Results.Conclusions.We propose an anterior spinal cord structure, the spinothalamic tract to be the target of IMRT-caused LS.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Medicine, Oregon Health & Science University, Mailcode KPV4, 3181 Southwest Sam Jackson Park Road, Portland, OR 97239-3098, USA.

ABSTRACT
Background. Lhermitte's sign (LS) is a benign form of myelopathy with neck flexion producing an unpleasant electric-shock sensation radiating down the extremities. Although rare, it can occur after head and neck radiotherapy. Results. We report a case of Lhermitte's developing after curative intensity-modulated radiotherapy (IMRT) for a patient with locoregionally advanced oropharyngeal cancer. IMRT delivers a conformal dose of radiation in head and neck cancer resulting in a gradient of radiation dose throughout the spinal cord. Using IMRT, more dose is delivered to the anterior spinal cord than the posterior cord. Conclusions. Lhermitte's sign can develop after IMRT for head and neck cancer. We propose an anterior spinal cord structure, the spinothalamic tract to be the target of IMRT-caused LS.

No MeSH data available.


Related in: MedlinePlus