Spine Surgery In Prone Position Research Articles

Unilateral visual loss due to central retinal artery occlusion with total ophthalmoplegia following cervical spine surgery in prone position.

Blindness after spinal surgery is a rare complication, but it is serious, irreversible and incurable. Central retinal artery occlusion (CRAO) is rare after spinal surgery and ophthalmoplegia is even rarer. A 52-year-old male patient complained of loss of vision in right eye immediately after cervical spine surgery. On examination, the patient's visual acuity in right eye was absent perception of light. Right eye pupil was dialated and relative afferent pupillary defect (RAPD) was present. Extraocular movements were absent in all gazes in right eye. Intra-ocular pressure (IOP) was 26 mmHg in right eye and 16 mmHg in the left. Posterior segment examination revealed blurred disc margin with ischemic whitening of retina, thin and attenuated retinal arterioles and a central cherry red spot in right eye. Left eye was essentially normal. The causal factors of blindness in the patient were likely ischemia of the retina after venous congestion or temporary arterial occlusion resulting from changes in pressure to the tissues of the orbit. Factors including prolonged prone positioning with head end dependent position and possibility of orbital compression by the headrest could have contributed to impaired venous drainage, increase in IOP and reduction in perfusion pressure. Loss of vision post spinal surgery is a rarest of complication yet grave and irreversible. Because the problem involves mainly prone positioning of the patient, an appropriate position should be found so that facial and ocular compression can be avoided.

Oesophageal Doppler to optimize intraoperative haemodynamics during prone position. A randomized controlled trial

BackgroundIntraoperative use of oesophageal Doppler (OD) was associated with improved postoperative outcomes through the optimization of perioperative fluid management. We studied the effect on haemodynamics of a goal-directed fluid management approach, guided by OD, during elective spine surgery in the prone position. MethodsIntraoperative fluid and vasopressor administration were directed according to one of two randomly chosen decision-making algorithms driven by either OD (OD group; n=33 patients) or standard parameters (standard group; n=34 patients). Both groups were monitored by OD, however haemodynamics management in the standard group was blinded to OD information. OD algorithm used corrected flow time as the primary variable to guide haemodynamics management. Mean arterial blood pressure (MAP) was maintained within 75% of the preoperative value for both groups. The primary outcome was the duration of intraoperative hypotensive episodes during prone position. ResultsThe proportion of procedure duration with MAP below the predefined threshold was greater in the Standard group than in the OD group: 34% (15–62) (median, interquartile range) versus 17% (5–35) of the observation period, respectively (P=0.01). They were also more frequent in the Standard group: 7 (3–11) per patient versus 3 (1–7) per patient (P<0.001). The requirement and dosing of ephedrine and infused colloids over the observation period did not significantly differ between the two groups. The OD parameters were comparable between the two groups during prone position. ConclusionOD monitoring during spine surgery in prone position is feasible and may help physicians to reduce the duration of hypotensive episodes during this surgical procedure.

Anaesthetic concerns of a pregnant patient with Pott's spine for spine surgery in prone position.

Sir, Surgical decompression is the treatment of choice in pregnancy complicated by spinal tuberculosis with neurologic deficit.[1] We report the anaesthetic management of a pregnant patient with Pott's spine in prone position and discuss the various anaesthetic concerns including haemodynamic instability. A 23-year-old multipara, 17 weeks of gestation, weighing 52 kg, with Pott's spine involving T7–T10 segments with progressive neurological deficit was scheduled for decompression and posterior screw fixation. Obstetrician's opinion was sought. Preoperative foetal heart rate (FHR) was documented. Anti-aspiration prophylaxis was administered. Her baseline HR was 112/min and blood pressure (BP) was 132/82 mmHg. Invasive arterial BP monitoring could not be done due to the logistic problems. General anaesthesia was induced with propofol and morphine. Endotracheal intubation was facilitated using vecuronium with size 7.0 orotracheal cuffed tube. Injection glycopyrrolate 0.2 mg was administered as anti-sialagogue. Anaesthesia was maintained with isoflurane in 50% nitrous oxide and oxygen mixture. Soon following positioning, patient developed hypotension i.e., more than 20% fall from the baseline systolic BP (SBP). Fluid replacement and pressure-free abdomen were rechecked but the SBP continued to remain between 90 and 100 mmHg. Initially, hydrocortisone 100 mg was administered intravenously. The oozing from the surgical site resolved following injection tranexamic acid 500 mg. Surgery lasted for 5 h but BP persisted in the same aforementioned range. Blood loss was 1000 ml approximately. Haemodynamics and FHR remained stable post-operatively. The anaesthetic concerns related to spine surgery in pregnant patient include both obstetric and surgery-related i.e., prolonged surgery in prone position, major blood loss, relative hypotension and risk of postoperative visual loss.[2] The risk of radiation is of paramount concern due to the inability to use abdominal shield and the proximity of radiation to the foetus. The additional problem with prone position here includes the inability to perform emergent caesarean section. Technical problems may limit the usefulness of continuous FHR monitoring between 16 and 20 weeks and it is recommended to document FHR before and after surgery which was done in our patient. The American College of Obstetricians and Gynaecologists recommends continuous FHR monitoring in non-obstetric surgery from 18 to 20 weeks of gestation, based on the patient and the surgery to be performed.[3] There has been controversy related to the use of controlled hypotension and intraoperative tests/monitoring to detect spinal cord injury during pregnancy. Invasive arterial BP monitoring must be performed, more so, if controlled hypotension is instituted. Various risk factors for haemodynamic instability in these patients include pregnancy-induced aortocaval compression, massive fluid shift, blood loss and prolonged surgery. In addition, autonomic dysfunction has been reported as the cause for high incidence of intraoperative hypotension in adult patients with thoracic spine tuberculosis.[4] In our patient, vasopressor was not considered to treat hypotension:First, because, as the SBP remained in the acceptable range of 90–100 mmHg, and second, its use could have further led to increased blood loss. Since the hypotension occurred soon after positioning, it could be attributed by factors such as pregnancy-induced aortocaval compression, pre-operative hydration status and autonomic neuropathy related to thoracic spine tuberculosis. The initial two factors were ruled out by ensuring adequate fluid replacement and free and hanging abdomen in prone position. It is also reported that prone position in pregnant patient is associated with lesser risk of aortocaval compression than sitting or lateral position.[5] To conclude, intraoperative haemodynamic stability is of paramount anaesthetic concern in pregnant patients with thoracic spine tuberculosis and autonomic dysfunction must be considered as a potential cause for intraoperative hypotension. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Quantifying the Amount of Bleeding and Associated Changes in Intra-Abdominal Pressure and Mean Airway Pressure in Patients Undergoing Lumbar Fixation Surgeries: A Comparison of Three Positioning Systems.

Study DesignProspective, randomised controlled, single centre study of 45 patients posted for two level lumbar fixation surgery in the prone position.PurposeTo compare intra-abdominal pressure (IAP), mean airway pressure mean airway pressure and blood loss during the spine surgery in prone position using three different positioning systems.Overview of LiteratureStudies have correlated IAP with the amount of perioperative bleeding. However, IAP and airway pressures while assessing the bleeding comparing two or more prone positioning systems are unclear.MethodsThis prospective study was conducted on a cohort of 45 patients scheduled for two-level lumbar fixation. Patients were randomly allocated to a spine table, Wilson's frame, and thermomodulated pads. Bladder pressure as an indicator of IAP, mean and peak airway pressures, and blood loss were monitored.ResultsIAP increased whenever patient position was changed to prone .The increase in pressure was more in the Wilson's frame group but was statistically significant only on prolonged positioning. Adopting the prone position always increased the mean airway pressure, but the increased was significant only in the Wilson's frame group. Mean airway pressure decreased in the spine table group and was statistically significant. The blood loss in the spine table group was significantly less as compared to the other groups.ConclusionsPositioning on a spine table results in less blood loss and low mean airway pressure. The Wilson's frame results in high IAP, increased mean airway pressure, and more blood loss. The thermomodulated frame increases mean airway pressure and produces a moderate increase in IAP and airway pressure.

Vasoplegic syndrome: A challenge to anaesthetic management

AbstractPerioperative hypotension is a well-recognized and relatively common problem during surgery. Vasoplegic syndrome is one such condition which is characterized by severe persistent hypotension with normal to high cardiac output and low systemic resistance. It is commonly seen in patients undergoing cardiac surgery on cardiopulmonary bypass. However, this syndrome has also been reported in off pump surgeries. Management of intraoperative hypotension may be challenging for an anaesthesiologist, if it does not respond or poorly respond to conventional therapy. We report the management of a hypertensive patient posted for spine surgery in prone position, who developed severe hypotension under anaesthesia refractory to treatment.

Керована гіпотензія при оперативних втручаннях на хребті у положенні на животі

Background. Deliberate hypotension during spinal surgery aims to reduce intraoperative bleeding, thus providing better surgical visualization and less requirements for transfusion. A lot of methods of controlled hypotension are used nowadays. Each of them has advantages and disadvantages.The aim of study was to examine safety and efficacy of hypotensive drug urapidil for providing deliberate hypotension for spinal surgery in prone position.Material and methods. Eighty patients were elected and divided into 2 groups. Patients of the 1st group (n=43) received urapidil for controlled hypotension intraoperatively and patients of the 2nd group did not receive hypotensive drugs intraoperatively. Hemodynamics, time of surgery and restoration of consciousness after general anesthesia (Bidway test 20 min after anesthesia).Results. Patients in urapidil group had reduction of blood pressure to desirable level without any critical drops of hemodynamics comparing to the patients of 2nd group (p&lt;0,05) whose blood pressure did not change significantly during surgery. Controlled hypotension allowed to reduce the surgery time comparing to patients without hypotension (p&lt;0,05). Awaking time (Bidway test) did not differ significantly between groups. No anesthesia complications were found during examination.Conclusion. Deliberate hypotension with urapidil is safe and effective during spinal surgery in prone position as it allows to provide good surgical visualization without adverse effects

Missing the 'window' might shut the light forever: Central retinal artery occlusion following spine surgery.

Missing the 'window' might shut the light forever: Central retinal artery occlusion following spine surgery.

Comparison of pressure-controlled and volume-controlled ventilation in patients undergoing spinal surgery in prone position supported by a Wilson frame

Objective To compare the pressure-controlled ventilation (PCV) and volume-controlled ventilation (VCV) in the patients undergoing spinal surgery in prone position supported by a Wilson frame.Methods Forty patients,of ASA physical status Ⅰ or Ⅱ,aged 30-64 yr,with body mass index ＜ 30 kg/m2,scheduled for elective spinal surgery in prone position supported by a Wilson frame under general anesthesia,were randomly allocated to receive mechanical ventilation using either VCV (n =20) or PCV (n =20) mode.Endotracheal intubation and mechanical ventilation were performed after induction of anesthesia.The tidal volume (VT) was set at 10 ml/kg according to the ideal body weight in group VCV.The maximal inspiratory pressure of the anesthesia machine was adjusted to maintain the VT at 10 ml/kg in group P.Both ventilation modes were required to maintain PET CO2 within the normal range.VT,respiratory rate,minute ventilation (MV),dynamic lung compliance (Cdyn),peak and mean airway pressure (Ppeak,Pmean),mean arterial pressure (MAP) and HR were recorded at 10 min after the patients were turned to supine position and at 30 min after the patients were turned to prone position after intubation.Arterial blood samples were collected for blood gas analysis,and oxygenation index(OI) and physiologic dead space fraction (VD/VT) were calculated.Results Compared with those at 10 min after turning to supine position,Ppeak was significantly increased and Cdyn,VT and MV were decreased at 30 min after turning to prone position in both groups.Compared with group VCV,Ppeak was significantly decreased,respiratory rate and Cdyn were increased,and no significant change was found in VT,MV,OI,VD/VT,Pmean,MAP and HR in PCV group.Conclusion Compared with VCV,PCV can improve the ventilatory efficacy and reduce the influence of prone position on respiratory dynamics in the patients undergoing spinal surgery in prone position supported by a Wilson frame. Key words: Respiration, artificial ; Prone position ; Wilson frame

Alteraciones del espesor de la capa de fibras nerviosas de la retina después de la cirugía de la columna vertebral en pronación: estudio prospectivo

Background and objectivesChanges in ocular perfusion play an important role in the pathogenesis of ischemic optic neuropathy. Ocular perfusion pressure is equal to mean arterial pressure minus intraocular pressure. The aim of this study was to evaluate the changes in the intraocular pressure and the retinal nerve fiber layer thickness in patients undergoing spinal surgery in the prone position. MethodsThis prospective study included 30 patients undergoing spinal surgery. Retinal nerve fiber layer thickness were measured one day before and after the surgery by using optical coherence tomography. Intraocular pressure was measured by tonopen six times at different position and time-duration: supine position (baseline); 10min after intubation (supine 1); 10min (prone 1), 60min (prone 2), 120min (prone 3) after prone position; and just after postoperative supine position (supine 2). ResultsOur study involved 10 male and 20 female patients with the median age of 57 years. When postoperative retinal nerve fiber layer thickness measurements were compared with preoperative values, a statistically significant thinning was observed in inferior and nasal quadrants (P=.009 and P=.003, respectively). We observed a statistically significant intraocular pressure decrease in Supine 1 and an increase in both Prone 2 and Prone 3 when compared to the baseline. Mean arterial pressure and ocular perfusion pressure were found to be significantly lower in prone 1, prone 2 and prone 3, when compared with the baseline. ConclusionsOur study has shown increase in intraocular pressure during spinal surgery in prone position. A statistically significant retinal nerve fiber layer thickness thinning was seen in inferior and nasal quadrants one day after the spinal surgery.

Alterações da espessura da camada de fibras nervosas da retina após cirurgia da coluna vertebral em pronação: estudo prospectivo

Background and objectivesChanges in ocular perfusion play an important role in the pathogenesis of ischemic optic neuropathy. Ocular perfusion pressure is equal to mean arterial pressure minus intraocular pressure. The aim of this study was to evaluate the changes in the intraocular pressure and the retinal nerve fiber layer thickness in patients undergoing spinal surgery in the prone position. MethodsThis prospective study included 30 patients undergoing spinal surgery. Retinal nerve fiber layer thickness were measured one day before and after the surgery by using optical coherence tomography. Intraocular pressure was measured by tonopen six times at different position and time‐duration: supine position (baseline); 10min after intubation (Supine 1); 10 (Prone 1), 60 (Prone 2), 120 (Prone 3)min after prone position; and just after postoperative supine position (Supine 2). ResultsOur study involved 10 male and 20 female patients with the median age of 57 years. When postoperative retinal nerve fiber layer thickness measurements were compared with preoperative values, a statistically significant thinning was observed in inferior and nasal quadrants (p=0.009 and p=0.003, respectively). We observed a statistically significant intraocular pressure decrease in Supine 1 and an increase in both Prone 2 and Prone 3 when compared to the baseline. Mean arterial pressure and ocular perfusion pressure were found to be significantly lower in Prone 1, Prone 2 and Prone 3, when compared with the baseline. ConclusionsOur study has shown increase in intraocular pressure during spinal surgery in prone position. A statistically significant retinal nerve fiber layer thickness thinning was seen in inferior and nasal quadrants one day after the spinal surgery.

Spinal anesthesia for lumbar spine surgery in prone position: plain vs heavy bupivacaine

Sytenko Institute of Spine and Joint Pathology AMS Ukraine, Dept of Anaesthesiology & Intensive Care, Kharkiv, Ukraine

Changes in retinal nerve fiber layer thickness after spinal surgery in the prone position: a prospective study

Background and objectivesChanges in ocular perfusion play an important role in the pathogenesis of ischemic optic neuropathy. Ocular perfusion pressure is equal to mean arterial pressure minus intraocular pressure. The aim of this study was to evaluate the changes in the intraocular pressure and the retinal nerve fiber layer thickness in patients undergoing spinal surgery in the prone position. MethodsThis prospective study included 30 patients undergoing spinal surgery. Retinal nerve fiber layer thickness were measured one day before and after the surgery by using optical coherence tomography. Intraocular pressure was measured by tonopen six times at different position and time-duration: supine position (baseline); 10min after intubation (Supine 1); 10 (Prone 1), 60 (Prone 2), 120 (Prone 3)min after prone position; and just after postoperative supine position (Supine 2). ResultsOur study involved 10 male and 20 female patients with the median age of 57 years. When postoperative retinal nerve fiber layer thickness measurements were compared with preoperative values, a statistically significant thinning was observed in inferior and nasal quadrants (p=0.009 and p=0.003, respectively). We observed a statistically significant intraocular pressure decrease in Supine 1 and an increase in both Prone 2 and Prone 3 when compared to the baseline. Mean arterial pressure and ocular perfusion pressure were found to be significantly lower in Prone 1, Prone 2 and Prone 3, when compared with the baseline. ConclusionsOur study has shown increase in intraocular pressure during spinal surgery in prone position. A statistically significant retinal nerve fiber layer thickness thinning was seen in inferior and nasal quadrants one day after the spinal surgery.

Effect of head rotation during surgery in the prone position on regional cerebral oxygen saturation

Near-infrared spectroscopy (NIRS) has been used to study regional cerebral blood oxygen saturation (rScO2) in patients in the prone position. We aimed to test the hypothesis that head rotation more than 45° would affect the rScO2. A prospective, controlled, single cohort study. University Hospital specialising in spinal surgery. Fifty-two patients undergoing spinal surgery in prone position were enrolled and 48 completed the study. NIRS sensors were attached to each side of the forehead. Measurements were conducted during steady-state anaesthesia with the head in the neutral position, rotated left, rotated right and returned to the neutral position. Each series consisted of three measurements: resting on the head support, during head lift (to relieve pressure on the tissue at the sensors) and returned to rest on the head support. The differences in rScO2 between the neutral and the turned head positions. For both left and right sensors, the median differences in rScO2 between neutral and left or right positions were between 0 and -1 with the head up (P = 0.14 to 0.84). The median differences with the head down were between 3.8 and -0.8, with a significant difference for the left sensor when turned left (P < 0.01) and for the right sensor (P = 0.006) when turned right. Ten patients showed reductions of more than 10 in rScO2 in the rotated (and lifted) positions. When the head was lifted from the head support, the rScO2 was -0.5 to 3.75 units higher, but there was high variability between patients. We recommend the neutral head position for prone patients.TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01760369.

More fluid administration may be needed in mild- to moderaterisk patients receiving spine surgery in prone position

China Medical University Hospital, Department of Anaesthesiology, Taichung City, Taiwan, Republic of China

Effects of duration of surgery flash-induced visual evoked potentials in patients undergoing spinal surgery in prone position

Objective To investigate the effects of duration of surgery on flash-induced visual evoked potentials (VEP) in patients undergoing spinal surgery in prone position.Methods Eighty-two ASA Ⅰ or Ⅱ patients of both sexes aged 20-76 yr weighing 43-96 kg undergoing spinal surgery in prone position were divided into 3 groups according to the duration of surgery:group S≤2 h ( n =34) ; group M 2-4 h ( n =38) and group L≥4 h ( n =10).VEP was monitored using protektor VEP monitoring device (Xltek Co.,Canada).The latency,amplitude and recovery time of wave P100 were recorded before and 10 min after induction of anesthesia and at the end of surgery.Results Compared with group S,the amplitude of wave P1000 was significantly decreased at the end of surgery in group M,the lantency of wave P100 was significantly prolonged,while the amplitude of wave P100 was decreased at the end of surgery in group L ( P ＜ 0.05).Compared with group M,the lantency of wave P100 was significantly prolonged,while the amplitude of wave P100 was decreased at the end of surgery in group L ( P ＜ 0.05).Compared with groups S and M,the recovery time of wave P100 was significantly prolonged in group L ( P ＜0.05).There was no significant difference in the recovery time of wave P100 between groups S and M ( P ＞ 0.05).Conclusion Duration of surgery (≥4 h) can affect flash-induced VEP,the longer the duration,the stronger the effects. Key words: Time; Surgical procedures,operative, Evoked potentials, visual; Spine

Cortical Blindness Following Spinal Surgery: Very Rare Cause of Perioperative Vision Loss

A 38-year-old man was operated with posterior spinal decompression and pedicle screw instrumentation for his L2 fracture with incomplete neurological deficit. In the recovery, he complained of blindness in both eyes after twelve hours. Computed tomographic scan and magnetic resonance angiography revealed bilateral occipital lobe infarcts. He remained permanently blind even after three years follow-up. Though rare, perioperative vision loss is a potential complication following spine surgery in prone position. We report a rare occurrence of cortical blindness following lumbar spine surgery.

Amaurosis after spine surgery: survey of the literature and discussion of one case

Postoperative vision loss (POVL) associated with spine surgery is a well known, albeit very rare complication. POVL incidence after spinal surgery ranges from 0.028 to 0.2%; however, due to the increase in number and duration of annual complex spinal operations, the incidence may increase. Origin and pathogenesis of POVL remain frequently unknown. A 73-year-old patient presented with lumbar disc herniation with associated neurological deficits after conservative pre-treatment at a peripheral hospital. Known comorbidities included arterial hypertension, moderate arterial sclerosis, diabetes mellitus type 2, mildly elevated blood lipids and treated prostate gland cancer. During lumbar spine surgery in modified prone position the patient presented with an acute episode of severe hypotension, which required treatment with catecholamines and Trendelenburg positioning. Three hours postoperatively, a visual loss in the right eye occurred, resulting in a complete amaurosis. Antihypertensive medication, arteriosclerosis and intraoperative hypotension are possible causes for the POVL. Intraoperative administration of catecholamines and Trendelenburg positioning for treatment of systemic hypotension might further compromise ocular perfusion. In patients with comorbidities compromising arterial blood pressure, blood circulation and microcirculation, POVL must be considered as a severe postoperative complication. It is recommended to inform patients about such complications and obtain preoperative informed consent regarding POVL. Any recent modification of antihypertensive medication must be reported and analysed for potential intraoperative hemodynamic consequences, prior to spine surgery in prone position.

Clinical study of the ways for the eye protection during spinal surgery in prone position

目的 探讨俯卧位脊柱手术患者术中预防性眼保护的措施.方法 40例俯卧位脊柱手术随机分成试验组(A组)和对照组(B组),每组20例.A组双眼结膜囊涂四环素眼膏后贴眼保护膜,在受压部位涂抹液体石蜡,摆放俯卧位后开始进行麻醉,术中定时对面部支撑点进行按摩,根据失血量1:1输血并维持平均动脉压(MAP)不低于90 mmHg;B组麻醉后摆放体位,双眼仅涂四环素眼膏,根据失血量1:1输注胶体,必要时输血.结果 A组较B组麻醉前后及改变体位前后血流动力学较稳定(P＜0.05).体位摆放时间较短(P＜0.01),皮肤受损及眼部并发症也较少(P＜0.05).结论 重视并全方位做好俯卧位脊柱手术患者眼部防护可有效预防眼部并发症的发生。

Unilateral postoperative visual loss due to central retinal artery occlusion following cervical spine surgery in prone position

Postoperative visual loss following spinal surgery is a rare complication. Although a number of intraoperative and postoperative factors have been implicated exact etiology still may remain unclear. We report a case of unilateral postoperative visual loss in a patient who had undergone prolonged spine surgery in a prone position.

Comparative Effects Of Propofol Infusion Versus Sevoflurane For Maintenance Of Anesthesia For Spine Surgery

Thirty patients of ASA grade I and II posted for elective spine surgery in prone position under general anesthesia were selected for the study. The patients were randomly assigned into two groups, Sevoflurane (Group S, n=15) and Propofol (Group P, n=15).A standard premedication and induction regimen was followed in all cases. Group S patients received N 2O / O 2 / Sevoflurane / Vecuronium and Group P received N 2O / O 2 / Propofol infusion / Vecuronium for maintenance of anesthesia to a desired level. Recovery was assessed with a simulated wake up test and a simple behavioral score was employed to assesses the over all recovery. The observation revealed that maintenance of anesthesia with sevoflurane was associated with a faster recovery than propofol anesthesia. But in a pharmacoeconomic based approach the increased cost of sevoflurane has to be linked with the benefits of rapid emergence.