- Email: [email protected]
Asymmetric postoperative visual loss after spine surgery in the lateral decubitus position
British Journal of Anaesthesia 101 (3): 380–2 (2008)
doi:10.1093/bja/aen163
Advance Access publication June 9, 2008
Case Report
Asymmetric postoperative visual loss after spine surgery in the lateral decubitus position J. W. Heitz* and P. B. Audu
*Corresponding author. E-mail: [email protected] Postoperative visual loss (POVL) is a rare but potentially devastating complication associated with spine surgery. In 1999, the American Society of Anesthesiologists Committee on Professional Liability established a POVL Registry to examine cases in search of common elements. Most cases of POVL after spine surgery which have been reported to the POVL Registry have been associated with intraoperative prone positioning. We present an atypical case that occurred after spine surgery performed in the lateral decubitus position. Br J Anaesth 2008; 101: 380–2 Keywords: complications; ophthalmic; position, lateral decubitus; surgery, spinal Accepted for publication: April 25, 2008
Case A 59-year-old woman presented for a discectomy and fusion via a thoracoscopic approach for treatment of a T8 –9 disc herniation causing thoracic myelopathy and progressive lower extremity weakness. Her co-morbidities included morbid obesity (BMI¼58.5), a 50 pack-yr cigarette smoking history, hypertension controlled with lasix, cardizem and atenolol, and type II diabetes mellitus. She had been treated with prednisone for her acute neurological symptoms and had since required insulin to maintain adequate glycemic control. Evaluation of her airway revealed several features consistent with possible difficult airway management including a modified-Mallampati Class IV airway, a short neck with limited extension and a large tongue. Awake fibreoptic intubation was therefore performed and a 35F left double lumen tube was placed. After i.v. induction, general anaesthesia was maintained with combined propofol and sufentanil infusions to facilitate motor and somatosensory-evoked potential monitoring. A 8.5F left subclavian cordis and a right radial arterial line were placed. Baseline blood pressure was 152/78 mm Hg. Blood pressure was maintained within 20% of baseline and monitored continuously by the arterial line. The patient was placed in a right lateral decubitus position with the head in a soft foam pillow. The eyes were in constant view of the anaesthetist with no extrinsic compression and were periodically reassessed during the procedure. Single lung ventilation was implemented to facilitate surgical exposure. The patient experienced several episodes of
desaturation (nadir PaO2¼58 mm Hg, nadir SpO2¼88%) and hypoventilation (highest PaCO2¼53 mm Hg) for no more than 10 min total, during lung separation which promptly improved with adjustments in ventilation. Surgical exposure was inadequate with a thorascopic approach and the surgeons converted to open thoracotomy approximately 2 h into the procedure. Serum glucose was maintained in the range of 187– 202 mg dl21. Preoperative Hgb was 14 g dl21 and postoperative Hgb was 12.6 g dl21. The surgical duration was approximately 7.5 h during which time the estimated blood loss was 250 ml, the urine output was 2000 ml, and 7000 ml of plasmalyte was administered. At the conclusion of the procedure, she was noted to have profound facial oedema, so extubation of the trachea was deferred until the next day. After the tracheal tube was removed in the next morning, the patient complained of diminished vision. Ophthalmologic consultation revealed complete visual loss in her right eye and perception of hand movement at 3 ft with her left. Bilateral afferent pupillary defects were noted. Fundoscopic examination was unremarkable without evidence of pallor, oedema, or haemorrhage. A diagnosis of posterior ischaemic optic neuropathy (PION) was made. Her subsequent postoperative course was disappointing and, at 2 months, revealed little improvement from her initial postoperative examination.
Discussion The most commonly reported cause of vision loss after spine surgery is PION, but its aetiology is not known. This
# The Board of Management and Trustees of the British Journal of Anaesthesia 2008. All rights reserved. For Permissions, please e-mail: [email protected]
Downloaded from http://bja.oxfordjournals.org/ at Centro de Estudos Do Hospital Felicio Rocho on August 16, 2015
Department of Anesthesiology, Jefferson Medical College, Thomas Jefferson University Hospital, Thomas Jefferson University, 111 S 11th St, Suite 8490, Philadelphia, PA 19107, USA
POVL after spine surgery
Changes in intraocular pressure under general anaesthesia are affected by patient positioning. Intraocular pressure has been demonstrated to increase under general anaesthesia in the prone position,8 9 but decreases in the dependent eye if the head is turned to one side10 or the patient is placed in full lateral decubitus position.11 Increased intraocular pressure is known to decrease perfusion in the anterior portion of the optic nerve, but probably has no effect on perfusion in the posterior portion. The slightly worse outcome in the dependant eye in this patient is consistent with the expectation that although intraocular pressure was probably lower in this eye during the procedure, this is not an important determinate for patients who develop PION. It should also be emphasized that asymmetric bilateral PION has also been reported in patients with profound facial oedema after spine surgery in prone position12 where the eyes would presumably be at the same level with respect to the heart. POVL from PION was unilateral in one-third of the patients reported to the Visual Loss Registry.1 Therefore, no definitive conclusions can be drawn from review of a single case in lateral decubitus position. The risk factors for POVL have yet to be fully elucidated. As no model currently exists to prospectively study this complication, retrospective examination of patients looking for commonality remains the best tool for determining the pathophysiology. Although exceptionally uncommon, examination of a sufficient number of cases that occur in the lateral decubitus position may be particularly enlightening.
References
381
1 Lee LA, Roth S, Posner KL, et al. The American Society of Anesthesiologists Postoperative Visual Loss Registry. Analysis of 93 spine cases with postoperative visual loss. Anesthesiology 2006; 105: 652 – 9 2 Warner ME, Warner MA, Garrity JA, MacKenzie RA, Warner DO. The frequency of perioperative vision loss. Anesth Analg 2001; 93: 1417 – 21 3 Chang SH, Miller NR. The incidence of vision loss due to perioperative ischemic optic neuropathy associated with spine surgery: The Johns Hopkins Hospital experience. Spine 2005; 30: 1299 – 302 4 Jeon YT, Park YO, won Hwang J, Lim YJ, Oh YS, Park HP. Effect of head position on postoperative chemosis after prone spinal surgery. J Neurosurg Anesthesiol 2007; 19: 1 – 4 5 Osei-Tutu LP, Grant GP, Turbin RE, et al. Effect of head elevation on intraocular pressure and retinal imaging in the prone position. (Abstract). J Neurosurg Anesthesiol 2006; 18: 278 6 Dunker S, Hsu H, Sebag J, Sadun A. Perioperative risk factors for posterior ischemic optic neuropathy. J Am Coll Surg 2002; 194: 705 – 10 7 Warner MA, Arens JF, Connis RT, et al. Practice advisory for perioperative visual loss associated with spine surgery. Anesthesiology 2006; 104: 1319– 28 8 Cheng MA, Todorov A, Tempelhoff R, McHugh T, Crowder CM, Lauryssen C. The effect of prone positioning on intraocular
Downloaded from http://bja.oxfordjournals.org/ at Centro de Estudos Do Hospital Felicio Rocho on August 16, 2015
patient had several of the patient-related risk factors associated with an increased risk of POVL, including a substantial tobacco history, diabetes mellitus, hypertension, and morbid obesity. Three procedure-related risk factors have also been identified by the ASA POVL Registry, specifically, prone positioning, estimated blood loss .1 litre, and surgical duration .6 h,1 but in this particular case only the duration of the procedure would have placed her at increased risk. Only two of the 93 spine patients in the POVL Registry were in lateral decubitus position for any portion of their procedure and none for the entire procedure. POVL after surgery performed exclusively in the lateral decubitus position has been infrequently reported.2 3 However, unlike surgery in the supine or prone position, the eyes are at a slightly different level with respect to the heart in the lateral decubitus position and consequently potentially exposed to slightly different disturbances of perfusion during surgery. No animal model exists for POVL, and its extremely low incidence renders it difficult to study in prospective fashion. As lateral decubitus positioning treats the two eyes of a single patient in slightly different fashion, these naturally occurring cases could be particularly informative in understanding the pathophysiology of POVL. Bilateral POVL may be caused by an overwhelming haemodynamic ocular insult. A milder insult could theoretically result in an asymmetric effect if it occurs while in the lateral decubitus position. Optic nerve perfusion pressure in its posterior portion is directly related to mean arterial pressure and inversely related to venous drainage pressure. Long procedures with substantial blood loss have been associated with POVL, but this may be because these procedures are typically associated with greater volume resuscitation. Apart from hypotension or anaemia associated with blood loss, increases in venous pressure from hypervolaemia and prone positioning could compromise posterior optic nerve perfusion. It is unclear if a differential in venous congestion could have contributed to the slightly better outcome in the non-dependent eye. In the prone position, slight head elevation has been demonstrated to reduce chemosis,4 but not choroidal venous congestion as seen on retinal imaging.5 This patient had visually impressive facial oedema at the conclusion of the procedure as had some of the other reported patients with POVL. Some authors have implicated facial oedema in the pathophysiology of PION,6 but a causal association between facial oedema and POVL has not been substantiated. The ASA Task Force on Perioperative Blindness found no reason to suspect facial oedema in the aetiology of POVL.7 However, facial oedema might be a marker for increased venous drainage pressure around the eyes or oedema of the optic nerve itself. Venous drainage pressure and facial oedema would be expected to be slightly greater for the dependant eye in lateral position which is consistent with the slightly worse outcome in this eye for this patient.
Heitz and Audu
pressure in anesthetized patients. Anesthesiology 2001; 95: 1351– 5 9 Hunt K, Bajekal R, Calder I, Meacher R, Eliahoo J, Acheson JF. Changes in intraocular pressure in anesthetized prone patients. J Neurosurg Anesthesiol 2004; 16: 287 – 90 10 Tiefenthaler W, Gabl M, Teuchner B, Benzer A. Intraocular pressure during lumbar disc surgery in the knee-elbow position. Anaesthesia 2005; 60: 878 – 81
11 Hwang JW, Jeon YT, Kim JH, Oh YS, Park HP. The effect of the lateral decubitus position on the intraocular pressure in anesthetized patients undergoing lung surgery. Acta Anaesthesiol Scand 2006; 50: 988 – 92 12 Kim JW, Hillis WL, Rizzo JF, Egan RA, Lessell S. Ischemic optic neuropathy following spine surgery in a 16-year-old patient and a ten-year-old patient. J Neuro-Ophthalmol 2006; 26: 30 – 3
Downloaded from http://bja.oxfordjournals.org/ at Centro de Estudos Do Hospital Felicio Rocho on August 16, 2015
382
doi:10.1093/bja/aen163
Advance Access publication June 9, 2008
Case Report
Asymmetric postoperative visual loss after spine surgery in the lateral decubitus position J. W. Heitz* and P. B. Audu
*Corresponding author. E-mail: [email protected] Postoperative visual loss (POVL) is a rare but potentially devastating complication associated with spine surgery. In 1999, the American Society of Anesthesiologists Committee on Professional Liability established a POVL Registry to examine cases in search of common elements. Most cases of POVL after spine surgery which have been reported to the POVL Registry have been associated with intraoperative prone positioning. We present an atypical case that occurred after spine surgery performed in the lateral decubitus position. Br J Anaesth 2008; 101: 380–2 Keywords: complications; ophthalmic; position, lateral decubitus; surgery, spinal Accepted for publication: April 25, 2008
Case A 59-year-old woman presented for a discectomy and fusion via a thoracoscopic approach for treatment of a T8 –9 disc herniation causing thoracic myelopathy and progressive lower extremity weakness. Her co-morbidities included morbid obesity (BMI¼58.5), a 50 pack-yr cigarette smoking history, hypertension controlled with lasix, cardizem and atenolol, and type II diabetes mellitus. She had been treated with prednisone for her acute neurological symptoms and had since required insulin to maintain adequate glycemic control. Evaluation of her airway revealed several features consistent with possible difficult airway management including a modified-Mallampati Class IV airway, a short neck with limited extension and a large tongue. Awake fibreoptic intubation was therefore performed and a 35F left double lumen tube was placed. After i.v. induction, general anaesthesia was maintained with combined propofol and sufentanil infusions to facilitate motor and somatosensory-evoked potential monitoring. A 8.5F left subclavian cordis and a right radial arterial line were placed. Baseline blood pressure was 152/78 mm Hg. Blood pressure was maintained within 20% of baseline and monitored continuously by the arterial line. The patient was placed in a right lateral decubitus position with the head in a soft foam pillow. The eyes were in constant view of the anaesthetist with no extrinsic compression and were periodically reassessed during the procedure. Single lung ventilation was implemented to facilitate surgical exposure. The patient experienced several episodes of
desaturation (nadir PaO2¼58 mm Hg, nadir SpO2¼88%) and hypoventilation (highest PaCO2¼53 mm Hg) for no more than 10 min total, during lung separation which promptly improved with adjustments in ventilation. Surgical exposure was inadequate with a thorascopic approach and the surgeons converted to open thoracotomy approximately 2 h into the procedure. Serum glucose was maintained in the range of 187– 202 mg dl21. Preoperative Hgb was 14 g dl21 and postoperative Hgb was 12.6 g dl21. The surgical duration was approximately 7.5 h during which time the estimated blood loss was 250 ml, the urine output was 2000 ml, and 7000 ml of plasmalyte was administered. At the conclusion of the procedure, she was noted to have profound facial oedema, so extubation of the trachea was deferred until the next day. After the tracheal tube was removed in the next morning, the patient complained of diminished vision. Ophthalmologic consultation revealed complete visual loss in her right eye and perception of hand movement at 3 ft with her left. Bilateral afferent pupillary defects were noted. Fundoscopic examination was unremarkable without evidence of pallor, oedema, or haemorrhage. A diagnosis of posterior ischaemic optic neuropathy (PION) was made. Her subsequent postoperative course was disappointing and, at 2 months, revealed little improvement from her initial postoperative examination.
Discussion The most commonly reported cause of vision loss after spine surgery is PION, but its aetiology is not known. This
# The Board of Management and Trustees of the British Journal of Anaesthesia 2008. All rights reserved. For Permissions, please e-mail: [email protected]
Downloaded from http://bja.oxfordjournals.org/ at Centro de Estudos Do Hospital Felicio Rocho on August 16, 2015
Department of Anesthesiology, Jefferson Medical College, Thomas Jefferson University Hospital, Thomas Jefferson University, 111 S 11th St, Suite 8490, Philadelphia, PA 19107, USA
POVL after spine surgery
Changes in intraocular pressure under general anaesthesia are affected by patient positioning. Intraocular pressure has been demonstrated to increase under general anaesthesia in the prone position,8 9 but decreases in the dependent eye if the head is turned to one side10 or the patient is placed in full lateral decubitus position.11 Increased intraocular pressure is known to decrease perfusion in the anterior portion of the optic nerve, but probably has no effect on perfusion in the posterior portion. The slightly worse outcome in the dependant eye in this patient is consistent with the expectation that although intraocular pressure was probably lower in this eye during the procedure, this is not an important determinate for patients who develop PION. It should also be emphasized that asymmetric bilateral PION has also been reported in patients with profound facial oedema after spine surgery in prone position12 where the eyes would presumably be at the same level with respect to the heart. POVL from PION was unilateral in one-third of the patients reported to the Visual Loss Registry.1 Therefore, no definitive conclusions can be drawn from review of a single case in lateral decubitus position. The risk factors for POVL have yet to be fully elucidated. As no model currently exists to prospectively study this complication, retrospective examination of patients looking for commonality remains the best tool for determining the pathophysiology. Although exceptionally uncommon, examination of a sufficient number of cases that occur in the lateral decubitus position may be particularly enlightening.
References
381
1 Lee LA, Roth S, Posner KL, et al. The American Society of Anesthesiologists Postoperative Visual Loss Registry. Analysis of 93 spine cases with postoperative visual loss. Anesthesiology 2006; 105: 652 – 9 2 Warner ME, Warner MA, Garrity JA, MacKenzie RA, Warner DO. The frequency of perioperative vision loss. Anesth Analg 2001; 93: 1417 – 21 3 Chang SH, Miller NR. The incidence of vision loss due to perioperative ischemic optic neuropathy associated with spine surgery: The Johns Hopkins Hospital experience. Spine 2005; 30: 1299 – 302 4 Jeon YT, Park YO, won Hwang J, Lim YJ, Oh YS, Park HP. Effect of head position on postoperative chemosis after prone spinal surgery. J Neurosurg Anesthesiol 2007; 19: 1 – 4 5 Osei-Tutu LP, Grant GP, Turbin RE, et al. Effect of head elevation on intraocular pressure and retinal imaging in the prone position. (Abstract). J Neurosurg Anesthesiol 2006; 18: 278 6 Dunker S, Hsu H, Sebag J, Sadun A. Perioperative risk factors for posterior ischemic optic neuropathy. J Am Coll Surg 2002; 194: 705 – 10 7 Warner MA, Arens JF, Connis RT, et al. Practice advisory for perioperative visual loss associated with spine surgery. Anesthesiology 2006; 104: 1319– 28 8 Cheng MA, Todorov A, Tempelhoff R, McHugh T, Crowder CM, Lauryssen C. The effect of prone positioning on intraocular
Downloaded from http://bja.oxfordjournals.org/ at Centro de Estudos Do Hospital Felicio Rocho on August 16, 2015
patient had several of the patient-related risk factors associated with an increased risk of POVL, including a substantial tobacco history, diabetes mellitus, hypertension, and morbid obesity. Three procedure-related risk factors have also been identified by the ASA POVL Registry, specifically, prone positioning, estimated blood loss .1 litre, and surgical duration .6 h,1 but in this particular case only the duration of the procedure would have placed her at increased risk. Only two of the 93 spine patients in the POVL Registry were in lateral decubitus position for any portion of their procedure and none for the entire procedure. POVL after surgery performed exclusively in the lateral decubitus position has been infrequently reported.2 3 However, unlike surgery in the supine or prone position, the eyes are at a slightly different level with respect to the heart in the lateral decubitus position and consequently potentially exposed to slightly different disturbances of perfusion during surgery. No animal model exists for POVL, and its extremely low incidence renders it difficult to study in prospective fashion. As lateral decubitus positioning treats the two eyes of a single patient in slightly different fashion, these naturally occurring cases could be particularly informative in understanding the pathophysiology of POVL. Bilateral POVL may be caused by an overwhelming haemodynamic ocular insult. A milder insult could theoretically result in an asymmetric effect if it occurs while in the lateral decubitus position. Optic nerve perfusion pressure in its posterior portion is directly related to mean arterial pressure and inversely related to venous drainage pressure. Long procedures with substantial blood loss have been associated with POVL, but this may be because these procedures are typically associated with greater volume resuscitation. Apart from hypotension or anaemia associated with blood loss, increases in venous pressure from hypervolaemia and prone positioning could compromise posterior optic nerve perfusion. It is unclear if a differential in venous congestion could have contributed to the slightly better outcome in the non-dependent eye. In the prone position, slight head elevation has been demonstrated to reduce chemosis,4 but not choroidal venous congestion as seen on retinal imaging.5 This patient had visually impressive facial oedema at the conclusion of the procedure as had some of the other reported patients with POVL. Some authors have implicated facial oedema in the pathophysiology of PION,6 but a causal association between facial oedema and POVL has not been substantiated. The ASA Task Force on Perioperative Blindness found no reason to suspect facial oedema in the aetiology of POVL.7 However, facial oedema might be a marker for increased venous drainage pressure around the eyes or oedema of the optic nerve itself. Venous drainage pressure and facial oedema would be expected to be slightly greater for the dependant eye in lateral position which is consistent with the slightly worse outcome in this eye for this patient.
Heitz and Audu
pressure in anesthetized patients. Anesthesiology 2001; 95: 1351– 5 9 Hunt K, Bajekal R, Calder I, Meacher R, Eliahoo J, Acheson JF. Changes in intraocular pressure in anesthetized prone patients. J Neurosurg Anesthesiol 2004; 16: 287 – 90 10 Tiefenthaler W, Gabl M, Teuchner B, Benzer A. Intraocular pressure during lumbar disc surgery in the knee-elbow position. Anaesthesia 2005; 60: 878 – 81
11 Hwang JW, Jeon YT, Kim JH, Oh YS, Park HP. The effect of the lateral decubitus position on the intraocular pressure in anesthetized patients undergoing lung surgery. Acta Anaesthesiol Scand 2006; 50: 988 – 92 12 Kim JW, Hillis WL, Rizzo JF, Egan RA, Lessell S. Ischemic optic neuropathy following spine surgery in a 16-year-old patient and a ten-year-old patient. J Neuro-Ophthalmol 2006; 26: 30 – 3
Downloaded from http://bja.oxfordjournals.org/ at Centro de Estudos Do Hospital Felicio Rocho on August 16, 2015
382