Indian Journal of Ophthalmology

CASE REPORT
Year
: 1990  |  Volume : 38  |  Issue : 2  |  Page : 70--73

Torsional Kestenbaum in congenital nystagmus with torticollis


Prem Prakash, AV Arya, Pradeep Sharma, V Menon Mahesh Chandra 
 Dr.R.P.Centre for Ophthalmic Sciences, A.I.I.M.S., New Delhi, India

Correspondence Address:
Prem Prakash
Dr.R.P.Centre for Ophthalmic Sciences, A.I.I.M.S., New Delhi 110 029
India

Abstract

Surgery in idiopathic congenital nystagmus to correct an abnormal head posture is based on the shifting of neutral point. Torsional Kestenbaum has been done in cases of congenital nystagmus with torticollis, without definite localisation of null point and sustained improvement of head posture subsequent to surgery has been attributed to presumed shift of the null point. We present a 6 year-old boy with congenital horizontal nystagmus with marked head tilt towards the left shoulder. Electronystagmography showed dampening of nystagmus on left tilt. Recession/advancement of all four oblique muscles was done to shift the null point and nystagmus dampened in the primary position eliminating the head tilt. This report emphasises the significance of electronystagmography in critical decision of horizontal/torsional Kestenbaum and documentation of innervational changes following surgery and subsequent followup.



How to cite this article:
Prakash P, Arya A V, Sharma P, Mahesh Chandra V M. Torsional Kestenbaum in congenital nystagmus with torticollis.Indian J Ophthalmol 1990;38:70-73


How to cite this URL:
Prakash P, Arya A V, Sharma P, Mahesh Chandra V M. Torsional Kestenbaum in congenital nystagmus with torticollis. Indian J Ophthalmol [serial online] 1990 [cited 2019 Nov 21 ];38:70-73
Available from: http://www.ijo.in/text.asp?1990/38/2/70/24533


Full Text

Congenital nystagmus is a clinical syndrome of involun­tary, regular, rhythmic oscillations of the eyes primarily in the horizontal plane. Nystagmus may diminish in a particular direction of gaze referred to as null point-the eccentric location of which will induce an abnormal head posture. Several surgical procedures have been reported in literature since 1950s [1],[2],[3],[4],[5],[6]. Surgical manipula­tion of the horizontal rectus muscles was proposed to eliminate the horizontal head posture by shifting of null point from the lateral gaze to the primary gaze. Pierse (1959) corrected a sagittal plane torticollis by operating on the vertical rectus muscles in both eyes [7]. Torsional Kestenbaum had been done in the European continent in caws of head tilt with amazing surgical success though the rationality is not clear [8] We present a case which had a face turn to the right and marked head tilt towards the left shoulder. We performed oblique muscle surgery to shift the null point. The pre-operative and post-operative observations and electronystagmographic findings are reported. The primary purpose of the present communication is to document electrophysiologically the innervational changes and nystagmus pattern changes following the surgical relocation of the null point by torsional Kestenbaum procedure to correct oblique plane torticollis in idiopathic congenital nystagmus.

 CASE REPORT



A 6 year-old male presented with the complaints of spontaneous to and fro movements of eyes since birth, inability to see the letters clearly on black-board in the school and reading with books very close to face. There was history of abnormal head positions while reading and while looking at a distant target. Systemic examina­tion including central nervous system examination was essentially normal.

Ocular examination revealed face turn to the right side (45°) while attempting to read the Snellen's chart from a distance of 6 meters and a marked head tilt towards The left shoulder (45°) while reading a book. The tilt effect was further enhanced by tilting the book to the right. (figs) Uniocular best corrected visual acuity was 6/6o in either eye which was same as binocular acuity with glasses with straight head. However binocular acuity with glasses improved to 6/ 36 with assumption of head posture. Near acuity was N 36 with head straight which improved to N8 after exaggeration of head pos­ture. Power of glasses was +1.0 DSph/ +0.25 DCyl x 90 0 either eye. Horizontal jerky nystagmus of gross amplitude with a frequency of about 90 oscillations per minute was observed in the primary position of gaze. Nystagmus remained horizontal while looking up or down, there being no vertical or rotatory nystagmus. The neutral zone was located in levoversion. The ocular movements were full and the child had no strabismus. No other ocular abnormality was found. Fundus viewed ophthalmoscopically after mydriasis did not reveal any rotatory nystagmus. Colour vision was normal. No horizontal or cyclovertical ocular oscilliopsia or ocular torsion could be demonstrated.

Electronystagmography was performed on Minogograf - 800 using four electrodes at two lateral and medial canthi, a neutral ground electrode on the centre of the forehead. Preoperative electronystagmogram showed a regular, low amplitude bidirectional jerk nystagmus of pseudopendular type with foveating saccades and dual jerk nystagmus with sinusoidal modulation of slow eye movements in levoversion [Figure 2]a which changed to gross amplitude, unidirectional pure jerk nystagmus in straight ahead gaze and on dextroversion [Figure 2]b & c. Recording on reading with head tilt towards the left shoulder or reading with book tilted with head straight caused dampening of nystagmus amplitude with regularity and change of characteristic of nystagmus waveform from jerk to pendular type with foveating saccades [Figure 2]d. However, near work with tilt towards the right shoulder exaggerated the intensity of jerk nys­tagmus [Figure 2]e

Keeping in view of the pattern of ocular torticollis, all the four oblique muscles were surgically tackled. In the right eye, the anterior fibers of the inferior oblique were recessed by 8mm while the anterior fibers of the superior oblique which are primarily concerned with intorsion, were advanced anterolaterally by Harada-Ito procedure. In the left eye, the insertion of the superior oblique was recessed by 8 mm while the anterior fibers of the inferior oblique were advanced under the lateral rectus by 8 mm. In immediate post-operative period, the patient kept his head as well as the book straight while reading [Figure 3] and while looking at a distant object. Though Snellen's acuity for distance was the same as pre-operatively, the patient felt an improvement in the quality of vision. There was no tilt or face turn for reading which he could now do comfortably.

Electronystagmography recorded one week postopera­tively revealed the maintenance of preoperative regular and fine amplitude pattern of nystagmus in levoversion [Figure 4]a and remarkable betterment in amplitude of jerk nystagmus in straight ahead gaze. [Figure 4]b and in dextroversion [Figure 4]c. Similarly while a regular pattern of nystagmus on left head tilt as observed pre-operative­ly was maintained [Figure 4]d head tilt towards the right shoulder while reading revealed improvement in nystag­mus amplitude, frequency and shift to pendular waveform [Figure 4]e.

 DISCUSSION



Congenital nystagmus with torticollis presents a big surgical challenge to relieve the dyscosmetic aspect of the condition as well as to improve comfort and quality of vision. The exact pathophysiologic mechanism of true congenital nystagmus is not known. However, torticollis in a congenital nystagmus with an eccentric position of null point is considered an innervational torticollis in which conjugate deviation of both eyes by assuming an abnormal head posture or vergence movement of eyes suppresses the nystagmus movements. This mechanism explains the horizontal torticollis manifest­ing as a face turn to the right side on distant fixation in our patient who had the null point in levoversion. But the concurrence of head tilt towards the left shoulder while doing fine near work like reading small letters or the preferential tilting of the book to the right side while head straight suggested subclinical muscular imbalances; the assumption of abnormal head position while reading reflected an attempt to attain the position of muscular equilibrium. This confirmed on electronystagmography as nystagmus dampened and assumed a more regular waveform on tilting the head to the left side. This obser­vation clearly shows that the null point is obtained by torsional eye movements. Oblique muscle surgery was done to correct the oblique plane torticollis which also spontaneously changed the innervational impulses to the neutral zone to the primary position thus correcting the abnormal head posture for distance and for near which has been well documented by electronystagmog­raphy postoperatively. The nystagmus intensity was diminished over all gaze angles in levoversion and the null zone appeared broadened and shifted towards the primary position. Since congenital nystagmus waveforms as depicted in the electronystagmogram indicate an attempt at increasing foveation time and a more stable fixation mechanism, a spontaneous im­provement in the visual acuity is expected as a conse­quence to aforesaid changes as the target is foveated for extended periods of time. We feel electronystagmog­raphy is an invaluable tool in documenting the nature of nystagmus, in confirming the position of a null zone, deciding the type of extraocular muscle surgery and evaluating the results of surgery.

References

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