Parmod K. Bithal

Effect of preemptive gabapentin on postoperative pain relief and morphine consumption following lumbar laminectomy and discectomy: a randomized, double-blinded, placebo-controlled study.

Synergism between gabapentin and morphine in treating incisional pain has been demonstrated in animal experiments and clinical studies. The efficacy of gabapentin for treatment of perioperative pain remains controversial. This study was designed to detect the influence of gabapentin premedication on morphine consumption in the immediate postoperative period in patients undergoing lumbar laminectomy and discectomy. Either gabapentin 800 mg (in two equally divided doses) or placebo was given preoperatively to 60 adult patients undergoing elective lumbar laminectomy or discectomy in a double-blinded, placebo-controlled, randomized study. Standard general anesthesia was given to all the patients. Morphine was administered via patient-controlled analgesia pump in the immediate postoperative period for first 8 hours. Pain at rest and on movement was assessed using a Verbal Rating Scale (VRS) every 2 hours for the first 8 postoperative hours. There were no differences in demographics or surgical duration between the two groups. The amount of fentanyl administered in the intraoperative period was similar between the two groups. In the postoperative period, the VRS score for pain at 0, 2, 4, 6, and 8 hours was not significantly different between the two groups. Highest median VRS score was recorded at 0 hours postoperatively in both groups (VRS: rest = 6, movement = 8 in placebo group; rest = 6, movement = 8 in gabapentin group). Total morphine consumption and side effects were similar in the two groups. Gabapentin does not decrease the morphine requirement or morphine side effects in the immediate postoperative period following lumbar laminectomy and discectomy.

Comparative incidence of venous air embolism and associated hypotension in adults and children operated for neurosurgery in the sitting position

Background and objective: Venous air embolism is a constant threat during neurosurgery performed in the sitting position. No large prospective study has compared the incidence of venous air embolism and associated hypotension between adults and children. Methods: Four hundred and thirty patients (334 adults, 96 children) scheduled to undergo planned posterior fossa surgery in the sitting position (between January 1989 to December 1994) were studied with end-tidal carbon dioxide monitoring. Intraoperatively, a sudden and sustained decrease in end-tidal carbon dioxide tension of >0.7 kPa was presumed to be due to venous air embolism. Management during the episode was on the established guidelines. Hypotension (decrease in systolic arterial pressure of 20% or more from the previous level) was treated with crystalloids and/or a vasopressor. Results: Capnometry detected a 28% incidence rate of air embolism in adults (93/334) and a 22% incidence rate in children (21/96) (P = 0.29). In both groups, the highest incidence rate of embolism took place during muscle handling (44% of adults versus 38% of children, P = 0.8). Embolic episodes were accompanied by hypotension in 37% of adults (34/93) and in 33% of children (7/21) (P = 0.98). To restore arterial pressure to pre-embolic levels, 53% of adults (18/34) and 43% of children (3/7) were administered vasopressors (P = 0.94). There was no intraoperative mortality. The surgical procedure on one adult was abandoned because of persistent hypotension following the embolic episode. Conclusion: The incidence of venous air embolism and consequent hypotension is similar in adults and children.

Sudden asystole during surgery in the cerebellopontine angle

SummaryWe report a case of a 40-year-old lady undergoing surgery for a tumor in the cerebellopontine angle. Intraoperatively, patient had a sudden asystole without prior warning sign of bradycardia. It could have been the severe form of trigeminocardiac reflex. The cardiac rhythm returned spontaneously once the surgical manipulation stopped. The remainder of the operation was uneventful and no complication occurred afterwards. The possible mechanism of the event is discussed.

Catheter malplacement during central venous cannulation through arm veins in pediatric patients.

For successful catheter placement, central venous cannulation (CVC) through internal jugular vein and subclavian vein has been recommended in both adult and pediatric patients. But it carries a risk of serious complications, such as pneumothorax, carotid, or subclavian artery puncture, which can be life-threatening, particularly in critically ill children. So a prospective study was carried out to determine the success rate of correct catheter tip placement during CVC through antecubital veins in pediatric neurosurgical patients. A total of 200 pediatric patients (age 1-15 years) of either sex were studied. Basilic or cephalic veins of either arm were selected. All the patients were cannulated in the operation room under general anesthesia. Single lumen, proper size catheters (with stillete) were used for cannulation. The catheter was inserted in supine position with the arm abducted at right angle to the body and neck turned ipsilaterally. The length of insertion was determined from cubital fossa to the right second intercostal space. The exact position of the tip of the catheter was confirmed radiologically in ICU. Correct catheter tip placement was achieved in 98 (49%) patients. Multivariate logistic regression analysis of data shows that there was no statistically significant difference among correct and incorrect catheter tip placement in relation to factors including sex, side of cannulation (left or right), and type of vein (basilic or cephalic). The analysis of correct catheter tip placement in relation to age showed that the highest success rate was achieved in children of age group 6 to 10 years (60.2%) followed by 30.6% in the 11 to 15 year group. The lowest success rate of tip placement of only 9.2% was observed in younger children of age 1 to 5 years, which is statistically significant (P = 0.001). Of 102 incorrect placements reported, 37% were in 1 to 5 year age group versus 9.2% correct tip placements. The most common unsatisfactory placements were either in the ipsilateral internal jugular vein (N = 38, 37.2%) or in the ipsilateral subclavian vein (N = 27, 26.4%). In 10 patients the catheter crossed over to the opposite subclavian vein, in 16 patients the catheter tips were found in the axillary vein, and in 10 patients each the catheter tip was observed in right atrium and right ventricle. No major complication during and following CVC was observed. To conclude, CVC using single orifice catheter through arm veins in pediatric patients is easy to perform, but the proper catheter tip placement is highly unreliable, particularly in younger children 1 to 5 years of age.

Preincision 0.25% bupivacaine scalp infiltration and postcraniotomy pain: a randomized double-blind, placebo-controlled study.

&NA; This prospective, double‐blind, randomized, and placebo‐controlled trial was performed to evaluate the effect of preincisional scalp infiltration with 0.25% bupivacaine on the postoperative pain perception and analgesic requirement of patients undergoing elective supratentorial craniotomy. Twenty patients (bupivacaine group) received scalp infiltration with 25 mL of 0.25% bupivacaine followed by intravenous 5 mL of saline as placebo 5 minutes before incision, and another 21 patients (fentanyl group) received scalp infiltration with a similar volume of 0.9% saline solution followed by 2 &mgr;g/kg of intravenous fentanyl 5 minutes before incision. Following standard anesthesia technique, basal, preincisional, and postincisional hemodynamic data were recorded. Postoperative pain was assessed at 1, 6, 12, 24, and 48 hours by using a 10‐cm visual analog scale. Diclofenac sodium was used as rescue analgesic in the postoperative period. Results showed rescue analgesic was required only during the first 12 hours. In each group the same number of patients needed rescue analgesia, but bupivacaine delayed this requirement 105 (30–720; median [range]) minutes compared with 60 (15–720; median [range]) minutes for the fentanyl group (P = 0.13). But there was no difference in the amount of analgesic consumed at different time intervals. Six of 20 patients in the bupivacaine group required rescue analgesic at the end of 1 hour compared with 9 of 21 fentanyl patients (P = 0.61). At 6 hours, the fraction of patients who required rescue analgesia were 7 of 20 and 11 of 21, respectively (P = 0.44). In conclusion, bupivacaine preincision scalp infiltration did not have any significant effect on postcraniotomy pain and analgesic requirement. However, bupivacaine may delay the requirement of the first analgesic dose.

Rupture of aorta and inferior vena cava during lumbar disc surgery

SummaryMajor vascular injury during lumbar disc surgery has been recognized as an unusual but well described complication. A potentially fatal outcome can be avoided by a high index of suspicion and an early diagnosis.We present a rare case of aortic and inferior vena caval injury in a 50-year-old female patient undergoing intervertebral disc surgery at lumbar one and two levels. A quick diagnosis and prompt management resulted in a favourable outcome for the patient.

Seizures following posterior fossa surgery.

A retrospective analysis of seizure incidence in 511 patients who underwent posterior possa operations via a suboccipital craniectomy with prophylactic anticonvulsant agents, was performed. Thirty patients (5.9%) experienced seizures within 2 weeks postoperatively. Their mean age was 15 years. Twenty patients had seizures within 3 h of operation; 24 patients had generalized tonic clonic seizures. Focal motor seizures with secondary generalization and simple focal motor seizures were recorded in three patients each. The incidence of postoperative seizures was highest in patients with acoustic schwanommas (9.09%) followed by those with medulloblastomas (8.54%) and astrocytomas (8.33%). The sitting position, associated with venous air embolism (VAE) and or pneumocephalus, was related to the occurrence (p = 0.001) of postoperative seizures. Seizures occurred in 24 patients out of 250 cases operated on in the sitting position compared with 3/170 and 3/91 in the prone and lateral positions, respectively. Intraoperatively significant VAE occurred in 10 out of 30 patients and postoperative computed tomography revealed pneunocephalus in 20 out of 30 patients. A higher percentage was found in patients with a preoperative ventriculoperitoneal shunt or intraoperative ventriculostomy (6.5%) than in those without (5.1%), but the difference was not statistically significant. In conclusion, seizures after posterior fossa surgery are a significant problem which is not reflected in the published literature. Our study highlights the significance of the sitting position in the causation of seizures after posterior fossa surgery.

Planning for early emergence in neurosurgical patients: a randomized prospective trial of low-dose anesthetics.

BACKGROUND: For early detection of a cerebral complication, rapid awakening from anesthesia is essential after craniotomy. Systemic hypertension is a major drawback associated with fast tracking, which may predispose to formation of intracranial hematoma. Although various drugs have been widely evaluated, there are limited data with regards to use of anesthetics to blunt emergence hypertension. We hypothesized that use of low-dose anesthetics during craniotomy closure facilitates early emergence with a decrease in hemodynamic consequences. METHODS: Three emergent techniques were evaluated in 150 normotensive adult patients operated for supratentorial tumors under standard isoflurane anesthesia. At the time of dural closure, the patients were randomized to receive low-dose propofol (3 mg · kg−1 · h−1), fentanyl (1.5 &mgr;g · kg−1 · h−1) or isoflurane (end-tidal concentration of 0.2%) until the beginning of skin closure. Nitrous oxide was discontinued after head dressing. RESULTS: Median time to emergence was 6 min with propofol, 4 min with fentanyl, and 5 min with isoflurane (P = 0.008). More patients had hypertension in the pre-extubation compared with extubation or postextubation phase (P = 0.009). Comparing the three groups, fewer patients required esmolol with fentanyl use overall, and in the pre-extubation phase (P = 0.01). Significant midline shift in the preoperative cerebral imaging scans was found to be an independent risk factor for emergence hypertension. CONCLUSIONS: Pain during surgical closure may be an important cause of sympathetic stimulation leading to emergence hypertension. The use of low-doses of fentanyl during craniotomy closure is more advantageous than propofol or isoflurane for early emergence in neurosurgical patients and is the most effective technique for preventing early postoperative hypertension.

Perioperative management of children with encephalocele: an institutional experience.

Background Encephaloceles are neural tube defects that are characterized by protrusion of the brain and meninges through a defect in the cranium. The inherent implications of pediatric anesthesia and difficult airway make surgical correction challenging for anesthesiologists Methods Available medical records of 118 children who underwent excision and repair of encephalocele over a period of 10 years were analyzed retrospectively. Data on associated anomalies, anesthetic management, perioperative complications, and outcome at discharge were reviewed. Results The average age of presentation was 1 year and 6 months. The most common site of lesion was the occiput (67%). Encephaloceles were giant (size of sac larger than the head) in 15.3% of children. Hydrocephalus was the most common complication (45.8%) and was predominantly associated in children with occipital encephaloceles (P=0.00). Difficult mask ventilation and intubation were encountered in 5.9% and 19.5% of children, respectively. In children with occipital encephalocele, the trachea was intubated commonly by direct laryngoscopy in the lateral position (47.5%). The average blood loss was 69.6±13.2 mL, and 56 children required transfusion, the average being 13.2±9.6 mL/kg. Intraoperative hemodynamic disturbances and respiratory complications were observed in 21.1% and 13.5% of children, respectively. The mean intensive care unit and hospital stay were 1.8±2.1 and 8.6±4.9 days, respectively. The stays were prolonged significantly whenever the children developed hydrocephalus, meningitis, and respiratory infection, predisposing to poor outcome. Conclusions Difficult airway is not the only concern in children with encephalocele, but associated congenital malformations, hydrocephalus, large size of sac, and hemodynamic disturbances all require careful consideration.

The role of neuronavigation-guided functional MRI and diffusion tensor tractography along with cortical stimulation in patients with eloquent cortex lesions.

Abstract Objective. To effectively combine functional MRI (fMRI), diffusion tensor tractography (both guided by neuronavigation) along with cortical stimulation (CS) for surgery of eloquent cortex (EC) lesions. Materials and methods. Fifteen patients with lesions adjacent to the eloquent motor and sensory cortex were included. Preoperative fMRI and diffusion tensor imaging were performed and then integrated into the neuronavigation system. Intraoperative CS of sensory/motor cortex was performed to localize the EC under awake condition and this was correlated with areas active on fMRI utilizing neuronavigation. For excision of the deeper structures, CS, and tractography guided by neuronavigation were utilized. Results. A total of 127 cortical sites were evaluated with CS in 15 patients. The overall sensitivity, specificity, and accuracy of fMRI were 79%, 85%, and 82%, respectively, keeping the areas positive on CS as a referential parameter. Tractography helped in resecting the deeper areas of the tumor, but was not very accurate due to brain shift. However, it was useful in roughly assessing the deeper areas close to the long tracts. The risk of developing persistent neurological deficits was 6%. Pathologies included gliomas in ten patients, cavernous malformation in two patients, meningioma in one patient, and focal cortical dysplasia and Dysembryonic neuroepithelial tumor in one patient each. Near total excision was achieved in 7/10 (> 95% excision) gliomas and a total excision in all others lesions. Conclusions. Lesions directly over the EC present a special surgical challenge. The challenge lies in excising these lesions without producing any deficits. These goals may be achieved better by combined use of multimodal neuronavigation (fMRI and tractography) and intraoperative mapping with CS under awake conditions.