Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 59, Num. 4, 2011, pp. 649-651

Neurology India, Vol. 59, No. 4, July-August, 2011, pp. 649-651

Letter to Editor

Pin site bilateral epidural hematoma - A rare complication of using Mayfield clamp in neurosurgery

Vikas Naik, Nishant Goyal, Deepak Agrawal

Department of Neurosurgery and Gamma Knife, All India Institute of Medical Sciences, New Delhi, India
Correspondence Address: Deepak Agrawal, Department of Neurosurgery and Gamma Knife, All India Institute of Medical Sciences, New Delhi, India, drdeepak@gmail.com

Date of Submission: 18-Jun-2011
Date of Decision: 19-Jun-2011
Date of Acceptance: 22-Jun-2011

Code Number: ni11201

PMID: 21891964

DOI: 10.4103/0028-3886.84368

Sir,

Mayfield^® clamp is routinely used in neurosurgical practice and pins in Mayfield^® penetrate the outer cortex and make a very stable system for head fixation. Pin site infection, bleeding, air embolism, depressed skull fractures and brain parenchymal injury are complications associated with pin fixation systems like Mayfield clamp. ^{[1],[2],[3],[4],[5]} Children and even adults with prolonged hydrocephalus have thin skull bone and potential for injury to the underlying brain. Although unilateral pin site epidural hematoma (EDH) have been described, ^{[1],[2],[3],[4]} bilateral pin site epidural hematoma have not been documented till date.

A 40-year-old lady presented with history of progressive hearing loss of 4 years, headache of 18 months and blurring of vision of 4-month duration. On examination she had right side fifth, seventh, and eighth cranial nerve paresis and bilateral papilloedema. Contrast magnetic resonance imaging (MRI) of brain showed right vestibular schwannoma with communicating hydrocephalus [Figure - 1]a. Patient initially underwent a left ventriculoperitoneal shunt followed 1 week later by definitive surgery via retrosigmoid suboccipital approach. Patient was placed in lateral position with head fixed in a Mayfield^® clamp. Complete tumor excision was achieved. However, throughout the procedure cerebellum was found to be tense. Patient was shifted unreversed to the ICU. Computed tomography (CT) of head done in the immediate postoperative period showed large left frontal and right parietal epidural hematomas underlying the pin sites [Figure - 1]b. A repeat coagulation profile done at this time was also normal. Patient was taken up for urgent craniotomy and evacuation of bilateral EDH was done [Figure - 1]c. Patient made an uneventful recovery and was discharged on day 5 after surgery and remains on follow-up.

Head rest immobilizing the patient head has been routinely used in neurosurgical practice. Local puncture site infection, scalp vessel bleeding, air embolism, shunt tube damage, rarely depressed skull fracture and epidural hematoma have been reported. ^{[1],[2],[3],[4],[5]} Pin head rest causing hematoma is an extremely rare complication and to the best of authors' knowledge there have been only four case reports in literature. ^{[1],[2],[3],[4],[5]} To prevent such complications, head clamps has conic shape of the pins with pressure adjusting springs in the clamp. ^[1],[2],[3] Children and adults with chronic elevated intracranial pressure who have thin skull vault are more prone for depressed skull fracture and subsequent hematoma. The pin pressure is recommended not to exceed 60 psi for the Mayfield head clamps. In our case too, the pins were tightened till this reading and there was no obvious fracture of the skull clinically or on radiology (on postoperative CT head) [Figure 1 a and b].

Although deranged coagulation could be a factor in having multiple bleeds, our patient had a normal coagulation profile both pre- and postoperatively and no excessive bleeding was noted intraoperatively, We hypothesize that there might have been a small ooze from the bone at the pin site due to breach of inner cortex. Draining of cerebrospinal fluid from cisterns might have led to a loss of the tamponade effect leading to hematoma bilaterally at pin sites.

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