Neurosurg Focus / Volume 33 / August 2012

Neurosurg Focus 33 (2):E14, 2012

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PostoPerative visual loss after “prone-position” spine surgery is a rare but devastating postopera-tive complication in patients who undergo prone-

position procedures. The incidence and the mechanisms of visual loss after surgery are difficult to determine. The American Society of Anesthesiologists Postoperative Vi-sual Loss Registry arose in 2006.8 The incidence reported in the literature varies between 0.028% and 1.3%.3 How-ever, several case series and studies have been published recently, increasing the awareness of POVL among anes-thesiologists, spine surgeons, and ophthalmologists over the past 5–10 years. The procedures most commonly as-sociated with perioperative ION are coronary artery by-pass grafting and back or spine surgery.7

The 4 recognized causes of POVL are ION, CRAO, cortical infarction, and external ocular injury.3 The 2 dif-ferent forms of ION, anterior and posterior, are the most common (approximately 89%).3,7,8 The cause of the isch-emic damage to the optic nerve is still not completely understood, but perioperative anemia, perioperative hy-potension, increased venous pressure, head-down opera-tive position, increased CSF pressure, embolism, facial

or orbital edema, and direct ocular pressure are reported as the most common etiological factors.4,7,12 However, during the perioperative period, more than one hemo-dynamic parameter is altered, suggesting that the cause of ION may entail a combination of factors.4 In addition, preexisting comorbidities, such as systemic hypertension, hypercholesterolemia, diabetes mellitus, arteriosclerosis, heart disease, and smoking have been identified as addi-tional risk factors.6,7 Our conclusion is that ION appears to be caused by hemodynamic derangements in conjunction with a patient-specific susceptibility. Complete recovery of vision is seldom reported, and the prognosis for total visual recovery is low. The second most frequent cause of POVL identified in the literature (approximately 11%)3 is CRAO. It is usually caused by intraoperative compres-sion of the eye by the horseshoe headrest. External com-pression of the eye could increase intraocular pressure, decreasing perfusion pressure and causing CRAO.6

Relevant data reported that the anesthesiologist ex-amined the patient’s eyes in only 51% of the patients in whom ION was diagnosed after prone-position surgery.14 Most of the authors suggest particularly vigilant assess-ment of the eyes at the time of positioning and regularly during the procedure. Special emphasis should be given to protecting the eye against pressure during spine surger-

Current intraoperative devices to reduce visual loss after spine surgery

Alberto A. Uribe, M.D.,1 MirzA N. bAig, M.D., Ph.D.,2 erikA g. PUeNte, M.D.,1 ADolfo ViloriA, M.D.,1 ehUD MeNDel, M.D.,2 AND Sergio D. bergeSe, M.D.1

Departments of 1Anesthesiology and 2Neurological Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio

Postoperative visual loss (POVL) after spine surgery performed with the patient prone is a rare but devastating postoperative complication. The incidence and the mechanisms of visual loss after surgery are difficult to determine. The 4 recognized causes of POVL are ischemic optic neuropathy (approximately 89%), central retinal artery oc-clusion (approximately 11%), cortical infarction, and external ocular injury. There are very limited guidelines or protocols on the perioperative practice for “prone-position” surgeries. However, new devices have been designed to prevent mechanical ocular compression during prone-position spine surgeries. The authors used PubMed to perform a literature search for devices used in prone-position spine surgeries. A total of 7 devices was found; the authors explored these devices’ features, advantages, and disadvantages. The cause of POVL seems to be a multifactorial problem with unclear pathophysiological mechanisms. Therefore, ocular compression is a critical factor, and elimi-nating any obvious compression to the eye with these devices could possibly prevent this devastating perioperative complication.(http://thejns.org/doi/abs/10.3171/2009.8.FOCUS09151)

key WorDS      •      postoperative visual loss      •      central retinal artery occlusion      •      cortical infarction      •      ischemic optic neuropathy

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Abbreviations used in this paper: CRAO = central retinal artery occlusion; ION = ischemic optic neuropathy; LCD = liquid crystal display; OR = operating room; POVL = postoperative visual loss.

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ies, avoiding hypotension and hypovolemia, especially in patients with predisposing factors.6

There are many significant factors in POVL, and the pathophysiological mechanism of this syndrome is still unclear and probably multifactorial. However, several re-ports suggest that the most important factors related to POVL are adequate patient positioning and monitoring during prone-position surgeries.3 Experts agree that the patient’s head position should be placed at the level of or higher than the heart when possible.1 Even though POVL seems to be a multifactorial problem with unclear patho-physiological mechanisms, ocular compression is a criti-cal factor, and eliminating any obvious compression on the eye will prevent this devastating perioperative com-plication.

Ocular compression is mostly attributable to the dif-ficulty of positioning, monitoring, and accessing the pa-tient’s head before and during surgical procedures. To ad-dress these challenging factors and allow OR personnel to have complete control over head position and monitor-ing, classic devices have been modified and designed to prevent mechanical ocular compression during surgical procedures in which the patient is placed prone. Table 1 lists the advantages and disadvantages of each of the de-vices discussed below.

Classic Horseshoe-Shaped Headrest The patient’s head is held by this device and precari-

ously maintained by bandages. This device (Fig. 1) pro-vides inadequate stabilization of the head, allowing for an-teroposterior and lateral or rotatory movements. Also the headrest has contact with one of the eyes, even if these have been well protected from the beginning of the surgery.

Foam-Cushion Face Mask and  See-Through Operating Table

This device consists of a foam-based boxing helmet that is fitted on the patient before turning him or her to the prone position, guaranteeing that the face and eyes are free from pressure. This helmet also maintains the neck in a straight-line position, avoiding compression or torsion of the neck vessels and nerves, and maintaining accessible and safe airway devices. In addition, a clear plastic window placed under the head and neck region is used to control pressure on soft-tissue structures and to

TABLE 1: Devices used for surgery performed in patients in the prone position*

Device Advantages Disadvantages

classic horseshoe- shaped headrest

provides support of pt’s head provides inadequate stabilization of the head allows AP & lateral head movements

foam-cushion face mask & see-through operating table

maintains neck in a straight-line position mirror mounted underneath, allows real-time monitoring of pt’s face position & tubing

not available on the market does not allow adequate pt monitoring when sterile drapes are placed on top

OPTI-GARD eye pro- tector

protective mask for trauma or unintentional contact to the eyes compressive injuries have been reported when this device is used in conjunction w/ foam headrests

prone positioner (VOSS Medical Products)

minimizes pressure in the face & eyes highest surface pressures compared w/ other devices

ROHO neoprene pillow offers lower face-to-pillow interface pressures, providing a larger contact on the surface area of the chin skin

not disposable does not provide overall low face-to-pillow interface pressures; demonstrated to generate a higher inter- face pressure on the forehead

ProneView Protective Helmet System

allows an easy examination & monitoring of facial structures does not allow adequate pt monitoring when sterile drapes are placed on top or if OR lights are off

ProneView Video Cam- era Monitoring Sys- stem

allows monitoring of pt’s eyes & pressure-sensitive structures monitoring is direct & takes place in real time by looking at the image on the LCD monitor, even under the drapes device projects a clear image even when OR lights are off

more cables around the anesthesiology area does not have a standard setup for different types of tables used in prone-position cases does not provide options to adjust camera’s shooting direction

* AP = anteroposterior; pt = patient.

Fig. 1. Photograph of the classic horseshoe-shaped headrest.

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Devices for the prevention of postoperative visual loss

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supervise airway devices. A mirror mounted underneath allows for real-time monitoring of the patient’s face posi-tion and tubing for the duration of the surgery.11

OPTI-GARD Eye Protector This is a noncompressible eye protection mask used

to prevent trauma or any unintentional contact (Fig. 2). The OPTI-GARD is a latex-free, self-adhering lens pro-duced by Dupaco, Inc., that is marketed as a Class I FDA device and is categorized as an “ophthalmic shield.” This device is used in some institutions in addition to the head-rest. The eye protector is placed while the patient is still in the supine position. After the patient has been rolled over into the prone position, the anesthesiologist ensures the correct position of the device headrest.5 Although this de-vice has been created to protect the patient’s eyes against any unintentional contact, compressive injuries have been reported when it is used in conjunction with foam headrests. The injuries can occur when the OPTI-GARD plastic lens is loosened and/or compressed, resulting in a higher probability of inadvertent eye compression.13

VOSS Prone Positioner This is a disposable polyurethane foam prone head

positioner that is not contoured to the face, with a T-shaped hole for the eyes and nose (VOSS Medical Prod-ucts) (Fig. 3). It has the highest surface pressures com-pared with the other devices. The patient’s face is directly rested on the square-shaped foam, minimizing pressure on the face and eyes during prone-position procedures, thus preventing skin damage and ocular compression.2

ROHO Neoprene Pillow, “Dry Flotation” Device This device, made by The ROHO Group, is a wash-

able prone face positioner made of multiple adjustable neoprene air bladders that imitate cushions, which are used to prevent pressure ulcers in patients who need to be immobilized for long periods.10 According to a pres-sure surface study, this device offers lower face-to-pillow interface pressures due to a larger surface area in contact

with the chin skin. An advantage of this device is that it protects most facial structures from compression.

ProneView Protective Helmet System This system made by Dupaco, Inc. (Fig. 4) consists

of a rigid helmet, disposable soft-foam prone head posi-tioner insert, and a standard or an adjustable mirror. The foam is contoured to fit comfortably over the face and prevent contact with the eyes, nose, and mouth. It widely distributes the pressures among the head’s bony struc-tures to reduce surface pressure on the face. This system is applied after induction of anesthesia and intubation. The endotracheal tube needs to be disconnected to set up the device and place the patient prone. The helmet can be held using anterior pressure with one hand while the other hand provides support in the opposite direc-tion around the patient’s occipital region. The patient can then be rolled on top of the OR table, and finally the legs of the helmet can be placed on top of the mirror. After reconnecting the endotracheal tube and confirming ad-equate ventilation, the facial structures can be examined by direct vision through the mirror to verify any changes in the position of the face during rollover.9 This device allows easy examination and monitoring of facial struc-tures during prone-position procedures. According to a facial and periorbital pressure point study, this device of-fers less surface pressure than a regular prone-positioner foam support.2

ProneView Video Camera Monitoring System The ProneView Video Camera Monitoring System,

made by Dupaco, Inc. (Fig. 5) is a new intraoperative device system that consists of the ProneView Protective Helmet System, an LCD monitor, and a camera cartridge. The correct setup of this device is similar to that for the

Fig. 2. Photograph of a patient wearing the OPTI-GARD eye protec-tor before intubation and placement in the prone position.

Fig. 3. Photograph of the VOSS prone head positioner from VOSS Medical Products.

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ProneView Protective Helmet System: the cushion is fit-ted inside the ProneView helmet and placed on the pa-tient’s face, making sure the eyebrows are visible, while the patient is supine. The ProneView helmet is held se-curely on the face during the turn into the prone posi-tion. After turning the patient prone onto the mirror cam-era platform, the face and cushion are rechecked for fit, and adequate position of the face and endotracheal tube is ensured. The LCD monitor, placed near the anesthe-siologist, projects the image from the camera, which is shooting directly into the patient’s face in real time. The role of this system is to provide anesthesiologists with a monitoring device that will allow direct and continuous visual access to the patient’s eyes and pressure-sensitive facial structures during prone-position procedures from above the patient by simply looking at the LCD monitor. This can even be used when drapes are placed over the patient’s head or lights are turned off during surgery. An-other advantage of this monitoring system is that it allows close monitoring regardless of the particular setup of the OR and equipment. For example, this system works when the anesthesiologist and anesthesia equipment are located facing the patient’s feet, impeding immediate access to the patient’s head.

The Department of Anesthesiology at The Ohio State

University Medical Center has been using the ProneView Video Camera Monitoring System for most patients who undergo general anesthesia during surgery in the prone position. The LCD monitor is attached to the Jackson ta-bles to facilitate its use during these cases. This strategic setup of the LCD monitor allows for the easy and contin-uous monitoring of the patient’s head, eyes, nose, mouth, and pressure-sensitive structures in real time. This en-sures that a safe position is maintained and that the endo-tracheal tube is not displaced during each case, confirm-ing the advantages of this new intraoperative monitoring technique for these types of surgeries. According to our experience at the Ohio State University Medical Center, the use of this new monitoring system has been a positive experience; it is user-friendly and easily installed. At our institution, we consider it to be a promising device for the prevention of POVL and other related prone-position fa-cial injuries because it shows a current and clear image of the face position. It also allows anesthesiologists to moni-tor inadvertent head movement closely, and therefore to make immediate adjustments to reposition the head in the cushion and ProneView helmet as needed. Although we recommend that further studies be done to confirm the

Fig. 4. Photographs of the ProneView table platform (lower), and a patient in the prone position with the ProneView Protective Helmet System in place (upper).

Fig. 5. Photographs of a patient in the prone position showing the ProneView Video Camera Monitoring System setup.

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utility and advantages of this device, its use in our hospi-tal setting has not only been advantageous but reassuring as well.

ConclusionsPostoperative visual loss seems to be a multifactorial

problem with unclear pathophysiological mechanisms. Ocular compression is a critical factor, and eliminating any obvious compression to the eye will help in prevent-ing this devastating perioperative complication. There are only very limited guidelines or protocols on periopera-tive practice for prone-position surgeries. However, new devices have been designed to prevent mechanical ocu-lar compression during surgical procedures in the prone position. However, these devices do not currently allow anesthesiologists to optimize the position of the head ac-cording to the facial surface pressure points and to ensure that all pressure-sensitive structures are placed correctly during surgery while the patient is in the prone position. Developing new devices that include simple surface pres-sure measurements will potentially allow anesthesiolo-gists to minimize the incidence of devastating postopera-tive complications, including POVL, in prone-position procedures.

Disclosure 

The authors report no conflict of interest concerning the mate-rials or methods used in this study or the findings specified in this paper.

Author contributions to the study and manuscript preparation include the following. Conception and design: Bergese, Uribe, Baig, Puente, Mendel. Acquisition of data: Uribe, Viloria. Analysis and interpretation of data: Uribe, Mendel. Drafting the article: Uribe. Critically revising the article: all authors. Administrative/technical/material support: Bergese, Uribe, Viloria. Study supervision: Uribe.

Acknowledgment

The authors acknowledge Keri Hudec, technical editor at The Ohio State University Medical Center Department of Anesthesiology.

References

1. Arens J, Warner M: Practice advisory for perioperative visual loss associated with spine surgery: a report by the American Society of Anesthesiologists Task Force on Perioperative Blindness. Anesthesiology 104:1319–1328, 2006

2. Atwater BI, Wahrenbrock E, Benumof JL, Mazzei WJ: Pres-sure on the face while in the prone position: ProneView versus Prone Positioner. J Clin Anesth 16:111–116, 2004

3. Baig MN, Lubow M, Immesoete P, Bergese SD, Hamdy EA, Mendel E: Vision loss after spine surgery: review of the litera-ture and recommendations. Neurosurg Focus 23(5):E15, 2007

4. Buono LM, Foroozan R: Perioperative posterior ischemic optic neuropathy: review of the literature. Surv Ophthalmol 50:15–26, 2005

5. Haushofer L, Bhattacharyya M, Rochester I, Sakka SA: Does conventional practice prevent ocular complications in prone-position spinal surgery? J Perioper Pract 19:16–19, 2002

6. Hoff J, Varhaug P, Midelfart A, Lund-Johansen M: Acute vi-sual loss after spinal surgery. Acta Ophthalmol 88:490–492 2010

7. Holy SE, Tsai JH, McAllister RK, Smith KH: Perioperative ischemic optic neuropathy: a case control analysis of 126,666 surgical procedures at a single institution. Anesthesiology 110: 246–253, 2009

8. Lee LA, Roth S, Posner KL, Cheney FW, Caplan RA, Newman NJ, et al: The American Society of Anesthesiologists Postop-erative Visual Loss Registry: analysis of 93 spine surgery cases with postoperative visual loss. Anesthesiology 105:652–659, 2006

9. Mazzei WJ, Benumof JL: Eye injury issue leads to new protec-tive helmet device and research on face pressures from prone positioning on OR table. Anesthesia Patient Safety Founda-tion Newsletter 15:42–43, 2000

10. McMichael JC, Place HM: Face tissue pressures in prone posi-tioning: a comparison of 3 pillows. J Spinal Disord Tech 21: 508–513, 2008

11. Möllmann M, Henning M, Liljenqvist U, Wenk M: A foam-cushion face mask and a see-through operation table: a new set-up for face protection and increased safety in prone posi-tion. Br J Anaesth 99:597–598, 2007

12. Nakra D, Bala I, Pratap M: Unilateral postoperative visual loss due to central retinal artery occlusion following cervical spine surgery in prone position. Paediatr Anaesth 17:805–808, 2007

13. Roth S, Tung A, Ksiazek S: Visual loss in a prone-positioned spine surgery patient with the head on a foam headrest and goggles covering the eyes: an old complication with a new mechanism. Anesth Analg 104:1185–1187, 2007

14. Weiskopf RB, Feiner J, Lieberman J, Hu SS: Visual loss after spinal surgery. Anesthesiology 106:1250–1252, 2007

Manuscript submitted June 15, 2009.Accepted August 24, 2009.Please include this information when citing this paper: DOI:

10.3171/2009.8.FOCUS09151. Address correspondence to: Sergio D. Bergese, M.D., Depart-

ment of Anesthesiology, Ohio State University Medical Center, 410 West 10th Street, Columbus, Ohio 43210. email: Sergio.Bergese@osumc.edu.

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