Preoperative cephalhematoma size measured with computed tomography predicts intraoperative bleeding in pediatric patients undergoing cranioplasty

Background@#Cranioplasty for the treatment of cephalhematomas in small infants with limited blood volume is challenging because of massive bleeding. This study aimed to elucidate the correlation between cephalhematoma size and intraoperative blood loss and identify criteria that can predict large intraoperative blood loss. @*Methods@#We reviewed the medical records of 120 pediatric patients aged less than 24 months who underwent cranioplasty for treatment of a cephalhematoma. The cephalhematoma sizes in preoperative brain computed tomography (CT) were measured using ImageJ. @*Results@#Pearson correlation showed that the cephalhematoma size in the pre-operative brain CT was weakly correlated with intraoperative blood loss (Pearson coefficient = 0.192, P = 0.037). In a multivariable logistic regression analysis, a cephalhematoma size greater than 113.5 cm3 was found to be a risk factor for large blood loss. The area under the curve in the receiver operating characteristic plot of the multivariable model was 0.714 (0.619–0.809). @*Conclusions@#A cephalhematoma size cutoff value of 113.5 cm3, as measured in the preoperative CT imaging, can predict intraoperative blood loss exceeding 30% of the total body blood volume. The establishment of a transfusion strategy prior to surgery based on cephalhematoma size could be useful in pediatric cranioplasty.

Preoperative cephalhematoma size measured with computed tomography predicts intraoperative bleeding in pediatric patients undergoing cranioplasty

Background@#Cranioplasty for the treatment of cephalhematomas in small infants with limited blood volume is challenging because of massive bleeding. This study aimed to elucidate the correlation between cephalhematoma size and intraoperative blood loss and identify criteria that can predict large intraoperative blood loss. @*Methods@#We reviewed the medical records of 120 pediatric patients aged less than 24 months who underwent cranioplasty for treatment of a cephalhematoma. The cephalhematoma sizes in preoperative brain computed tomography (CT) were measured using ImageJ. @*Results@#Pearson correlation showed that the cephalhematoma size in the pre-operative brain CT was weakly correlated with intraoperative blood loss (Pearson coefficient = 0.192, P = 0.037). In a multivariable logistic regression analysis, a cephalhematoma size greater than 113.5 cm3 was found to be a risk factor for large blood loss. The area under the curve in the receiver operating characteristic plot of the multivariable model was 0.714 (0.619–0.809). @*Conclusions@#A cephalhematoma size cutoff value of 113.5 cm3, as measured in the preoperative CT imaging, can predict intraoperative blood loss exceeding 30% of the total body blood volume. The establishment of a transfusion strategy prior to surgery based on cephalhematoma size could be useful in pediatric cranioplasty.

Bleeding properties according to surgical sites during pediatric craniotomy: a retrospective study comparing the two stages of epilepsy surgery

Background@#During pediatric epilepsy surgery, due to low circulating blood volume, intraoperative bleeding can result in significant hemodynamic instability, thereby requiring meticulous hemodynamic and transfusion strategies. Knowing the source of bleeding during the procedure would allow medical staff to better prepare the perioperative protocols for these patients. We compared intraoperative bleeding between the first (involving skin to meninges) and second (involving brain parenchyma) stages of epilepsy surgery to investigate the differences between various anatomical sites. @*Methods@#We reviewed the electronic medical records of 102 pediatric patients < 14 years old who underwent two-stage epilepsy surgeries during January 2012–2016. Invasive subdural grids were placed via craniotomy during Stage 1 and the epileptogenic zone was removed during Stage 2 of the surgery. We compared the volume of intraoperative bleeding between these two surgeries and identified variables associated with bleeding using multivariate regression analysis. @*Results@#Both surgeries resulted in similar intraoperative bleeding (24 vs. 26 ml/kg, P = 0.835), but Stage 2 required greater volumes of blood transfusion than Stage 1 (18.4 vs. 14.8 ml/kg, P = 0.011). Massive bleeding was associated with patients < 7 years old in Stage 1 and weighing < 18 kg in Stage 2. @*Conclusions@#The volume of intraoperative bleeding was similar between the two stages of pediatric epilepsy surgery and was large enough to require blood transfusions. Thus, blood loss during pediatric epilepsy surgery occurred at both anatomic sites. This indicates the necessity of early preparation for blood transfusion in both stages of pediatric epilepsy surgery.

Accidental intracerebral injection and seizure during scalp nerve blocks for awake craniotomy in a previously craniotomized patient: a case report / 대한마취과학회지

A 34-year-old man who previously underwent a craniotomy due to oligodendroglioma was admitted with a diagnosis of recurrent brain tumor. An awake craniotomy was planned. Approximately 15 minutes after completing the scalp nerve block, his upper torso suddenly moved and trembled for 10 seconds, suggesting a generalized clonic seizure. He recovered gradually and fully in 55 minutes without any neurological sequelae. The emergency computed tomography scan revealed a localized fluid collection and small intracerebral hemorrhage nearby in the temporoparietal cortex beneath the skull defect. He underwent surgery under general anesthesia at 8 hours after the seizure and was discharged from the hospital after 10 days. This report documents the first case of generalized seizure that was caused by the accidental intracerebral injection of local anesthetics. Although the patient recovered completely, the clinical implications regarding the scalp infiltration technique in a patient with skull defects are discussed.

Comparison of Dexmedetomidine and Remifentanil on Airway Reflex and Hemodynamic Changes during Recovery after Craniotomy

PURPOSE: During emergence from anesthesia for a craniotomy, maintenance of hemodynamic stability and prompt evaluation of neurological status is mandatory. The aim of this prospective, randomized, double-blind study was to compare the effects of dexmedetomidine and remifentanil on airway reflex and hemodynamic change in patients undergoing craniotomy. MATERIALS AND METHODS: Seventy-four patients undergoing clipping of unruptured cerebral aneurysm were recruited. In the dexmedetomidine group, patients were administered dexmedetomidine (0.5 µg/kg) for 5 minutes, while the patients of the remifentanil group were administered remifentanil with an effect site concentration of 1.5 ng/mL until endotracheal extubation. The incidence and severity of cough and hemodynamic variables were measured during the recovery period. Hemodynamic variables, respiration rate, and sedation scale were measured after extubation and in the post-anesthetic care unit (PACU). RESULTS: The incidence of grade 2 and 3 cough at the point of extubation was 62.5% in the dexmedetomidine group and 53.1% in the remifentanil group (p=0.39). Mean arterial pressure (p=0.01) at admission to the PACU and heart rate (p=0.04 and 0.01, respectively) at admission and at 10 minutes in the PACU were significantly lower in the dexmedetomidine group. Respiration rate was significantly lower in the remifentanil group at 2 minutes (p<0.01) and 5 minutes (p<0.01) after extubation. CONCLUSION: We concluded that a single bolus of dexmedetomidine (0.5 µg/kg) and remifentanil infusion have equal effectiveness in attenuating coughing and hemodynamic changes in patients undergoing cerebral aneurysm clipping; however, dexmedetomidine leads to better preservation of respiration.

Comparison of the antiemetic effect of ramosetron with ondansetron in patients undergoing microvascular decompression with retromastoid craniotomy: a preliminary report / 대한마취과학회지

BACKGROUND: Microvascular decompression with retromastoid craniotomy carries an especially high risk of postoperative nausea and vomiting. In this study, we compare the antiemetic efficacy of ramosetron and ondansetron in patients undergoing microvascular decompression with retromastoid craniotomy. METHODS: Using balanced anesthesia with sevoflurane and remifentanil infusion, ondansetron 8 mg (group O, n = 31) or ramosetron 0.3 mg (group R, n = 31) was administered at the dural closure. The incidence and severity of postoperative nausea and vomiting, required rescue medications and the incidence of side effects were measured at post-anesthetic care unit, 6, 24 and 48 hours postoperatively. Independent t-tests and the chi-square test or Fisher's exact test were used for statistical analyses. RESULTS: There were no differences in the demographic data between groups, except for a slightly longer anesthetic duration of group R (P = 0.01). The overall postoperative 48 hour incidences of nausea and vomiting were 93.6 and 61.3% (group O), and 87.1 and 51.6% (group R), respectively. Patients in group R showed a less severe degree of nausea (P = 0.02) and a lower incidence of dizziness (P = 0.04) between 6 and 24 hours. CONCLUSIONS: The preventive efficacy of ramosetron when used for postoperative nausea and vomiting was similar to that of ondansetron up to 48 hours after surgery in patients undergoing microvascular decompression with retromastoid craniotomy. A larger randomized controlled trial is needed to confirm our findings.

Dexmedetomidine for Rigid Bronchoscopy in an Infant with Tracheal Web after Ventricular Septal Defect Patch Repair

We report herein successful rigid bronchoscopy with preserved spontaneous breathing of a 54-day-old infant with tracheal web associated with previous ventricular septal defect (VSD) repair. We considered the use of dexmedetomidine in conjunction with intermittent ketamine from the following three clinical aspects. First, this infant was suffering from respiratory distress with chest retraction, the cause of which was not revealed by a computerized scan of the neck and chest. Second, the patient was scheduled for rigid bronchoscopy, which is accompanied by brief but strong stimulation. Third, this infant underwent congenital VSD heart repair approximately 1 month earlier.

Remote cerebellar hemorrhage after unruptured cerebral aneurysm surgery: two cases report / 대한마취과학회지

Remote cerebellar hemorrhage (RCH) occurring distant to the site of original surgery, such as supratentorial or spinal surgery, is rare but potentially fatal. Because the pathophysiology of RCH is thought to be excessive cerebrospinal fluid drainage during the perioperative periods, its diagnosis usually depends on the occurrence of unexpected neurologic disturbances and/or postoperative brain computerized tomography imaging. Because of its rarity, RCH-associated neurologic disturbances such as delayed awakening or nausea and vomiting may often be misdiagnosed as the effects of residual anesthetics or the effect of postoperative analgesic agents unless radiologic images are taken. Treatment for RCH ranges from conservative treatment to decompressive craniectomy, with prognoses ranging from complete resolution to fatality. Here, we report two cases of RCH after surgical clipping of an unruptured cerebral aneurysm of the anterior communicating artery and review anesthetic considerations.

Effect of a single dose of esmolol on the bispectral index to endotracheal intubation during desflurane anesthesia / 대한마취과학회지

BACKGROUND: In this prospective, randomized, double-blind, placebo-controlled trial, we investigated the effect of a single dose of esmolol on the bispectral index (BIS) to endotracheal intubation during desflurane anesthesia. METHODS: After induction of anesthesia, 60 patients were mask-ventilated with desflurane (end-tidal 1 minimum alveolar concentration) for 5 min and then received either normal saline, esmolol 0.5 or 1 mg/kg, 1 min prior to intubation (control, esmolol-0.5 and esmolol-1 groups, n = 20/group). BIS, mean arterial pressure, and heart rate were measured prior to anesthesia induction and esmolol administration, immediately preceding intubation (time point 0), and every minute for 5 min after intubation (time point 1 to 5). At time point 0, 1 and 5, 5 ml of arterial blood was taken to measure plasma concentrations of norepinephrine and epinephrine. RESULTS: BIS increased significantly at 1 min after intubation when compared with pre-intubation values in all groups. Both mean arterial pressure and heart rate increased significantly 1 min after intubation when compared with preintubation values for all groups. Plasma epinephrine concentrations did not increase significantly after tracheal intubation in any of the groups. Norepinephrine increased at 1 min after intubation when compared with the preintubation values in the esmolol groups (P < 0.05). CONCLUSIONS: A single bolus of esmolol was unable to blunt the increase in BIS to endotracheal intubation during desflurane anesthesia.

General anesthetics: neuroprotective or neurotoxic?

Many historical general anesthetics have been waxed and waned in the market of anesthetic field, mostly due to organ toxicities related to their metabolism, active metabolites and biodegradation, or other reasons. Modern anesthetics available now are known to undergo metabolism to the extent of clinical insignificance compared with the old ones. However, animal studies provided extensive evidences showing that general anesthetics are neurotoxic or neuroprotective in certain circumstances along with the advancement of knowledge on simultaneous neural injury and healing processes. Until now, there have been few prospective randomized clinical trials conducted to reveal these two issues. In fact, the concerns of the long-term effect of anesthetics on cognitive and behavior decline seem to be in arrears compared with those of the immediate effect of anesthetics, such as the rapidity of onset/offset of action, intraoperative hemodynamic controls or postoperative nausea and vomiting, etc. At present, we anesthesiologists, are challenged with the rapidly changing environments, in which the elderly population grows or a variety of sedation depth are required especially for patients of extreme ages. Concerns on anesthetics' effects with double edged sword are mounting from basic scientists and/or anesthesiologists, as well as public society, such as FDA in US. Therefore, I review the current findings from animal and human researches regarding the anesthetic potentials for neuroprotection and/or neurotoxicity under certain circumstances and their links with findings of clinical researches.

Small dose of propofol combined with dexamethasone for postoperative vomiting in pediatric Moyamoya disease patients: a prospective, observer-blinded, randomized controlled study / 대한마취과학회지

BACKGROUND: For effective postoperative antiemetic management in pediatric moyamoya disease patients receiving fentanyl based postoperative analgesia, a multimodal approach has been recommended. The uncertain efficacy of ondansetron for pediatric neurosurgical patients or the possible antiemetic effect of small dose of propofol motivated us to evaluate the preventive effect of a subhypnotic dose of propofol combined with dexamethasone on postoperative vomiting (POV), especially during immediate postoperative periods. METHODS: In a prospective observer-blind randomized controlled study, we compared dexamethasone 0.15 mg/kg alone (Group D) with dexamethasone combined with propofol of 0.5 mg/kg (Group DP) in 60 pediatric patients, aged 4-17 years, who underwent indirect bypass surgery and received fentanyl-based postoperative analgesia. Occurrence of vomiting and pain score (Wong-Baker facial score) and requirement of rescue analgesic and antiemetic were continually measured (0-2, 2-6, 6-12 and 12-24 postoperative hours). For statistical analysis, in addition to the Fisher's exact test, a generalized linear mixed model (GLMM) and the linear mixed model (LMM) for repeated measures were used for vomiting and pain scores, respectively. RESULTS: There was no statistical significance of POV incidence, requirement of rescue analgesic and pain score between the two groups at any measured intervals. The incidence of POV was 53.3% during 24 hours in both groups, and was especially 6.7% and 13.3% (P = 0.671) during 0-2 hr and 16.7% and 23.3% (P = 0.748) during 2-6 hr in group D and group DP, respectively. CONCLUSIONS: A small dose of propofol combined with dexamethasone appears ineffective to preventing POV in pediatric moyamoya patients receiving continuous fentanyl infusion.

Use of dexmedetomidine for awake crainiotomy / 대한마취과학회지

No abstract available.

Effect of Charcoal Filter on the Emergence from Sevoflurane Anesthesia in a Semi-Closed Rebreathing Circuit

PURPOSE: A charcoal filter attached within the anesthetic circuit has been shown to efficiently adsorb halothane or isoflurane, thus hastening anesthetic recovery in low or minimal flow system. This study was intended to demonstrate whether the charcoal filter enhances the recovery time from sevoflurane anesthesia using a semi-closed circuit system. MATERIALS AND METHODS: Thirty healthy patients scheduled for elective surgery under sevoflurane anesthesia were randomly assigned to the charcoal filter or control group. Upon completion of surgery, the end-tidal concentration of sevoflurane was maintained at 2.0 vol%. A charcoal filter was attached to the expiratory limb of the breathing circuit of charcoal filter group subjects. After sevoflurane was discontinued, ventilation was controlled with the same minute volume as the intra-operative period at a fresh gas flow rate of 5 L.min(-1) with 100% O2. The elimination kinetics of sevoflurane from end-tidal concentration, Bispectral index and times of eye opening and extubation were obtained. RESULTS: The exponential time constant (tau) of alveolar sevoflurane concentration in the charcoal filter group was significantly shorter than that in the control group (1.7+/-0.5 vs. 2.5+/-1.1 min, p=0.008). The charcoal filter hastened rapid eye opening (11.1+/-3.8 vs. 14.8+/-3.0 min, p=0.007) and extubation (11.9+/-3.9 vs. 15.3+/-3.2 min, p=0.014), compared to the control group. CONCLUSION: A charcoal filter enhances the recovery from sevoflurane anesthesia with a semi-closed rebreathing circuit.

Anesthetic experience of a patient with Ohtahara syndrome: A case report / 대한마취과학회지

Ohtahara syndrome (OS) is a rare epileptic encephalopathy that is characterized by an abnormal electroencephalogram (EEG) and intractable seizures in the neonatal and early infantile period. The patient of this reported case was delivered normally at 39 weeks of gestation without any complication. One week after birth, seizures that were refractory to anticonvulsants started with repetitive clustered tonic spasms. The child had no abnormal findings on the initial laboratory investigations. But he was diagnosed with OS according to the frequent tonic spasms, an abnormal EEG pattern of suppression-burst and magnetic resonance imaging of cortical dysplasia. He was planned to undergo an operation for brain lesion. This report describes our experience with the general anesthetic management when we performed craniotomy and right hemispherotomy for a patient with OS.

Pseudoaneurysm in the inferior epigastric artery and scrotal hematoma following removal of a femoral vein catheter: A case report / 대한마취과학회지

We report a rare case of pseudoaneurysm of the inferior epigastric artery and inguinal hematoma extending to the scrotum following the removal of a femoral venous catheter in a 24-year-old male patient undergoing two consecutive neurosurgical procedures.

Correlations of preoperative hormonal changes with propofol and remifentanil requirements in pituitary adenoma patients

BACKGROUND: Anesthetic requirements are affected by the preoperative levels of some hormones. This study investigated to identify the hormonal status such as plasma level and maximal secretary capacity correlating with propofol and remifentanil requirements in pituitary adenoma patients who show various hormonal secretory states perioperatively. METHODS: From 51 adult female pituitary adenoma patients, preoperative basal values and maximal stimulated levels of various hormones related to the axis of hypothalamus-pituitary-target organs on combined pituitary function test were recorded. Total intravenous anesthesia using target controlled infusion with propofol and remifentanil was administered. The effect-site concentration (Ce) of propofol reaching anesthetic induction and the consumed dosages of propofol and remifentanil during operation were measured. Anesthetic maintenance was controlled within 30% of preanesthetic hemodynamic variables by remifentanil and within ranges of BIS 45 +/- 10 by propofol. Spearman correlations between hormonal status and anesthetic requirements such as propofol Ce for induction, total consumed doses of propofol and remifentanil were performed with a statistical significance at P of 0.05. RESULTS: The preoperative basal level of ACTH was correlated positively with propofol induction Ce and maintenance dose, and the maximal secretory capacity of prolactin also correlated positively with propofol induction Ce. Remifentanil consumption dose was not related with any hormones measured regardless of either preoperative basal levels or maximal secretory levels. CONCLUSIONS: Propofol requirements may be related with preoperative plasma level of ACTH or maximal secretory capacity of prolactin.

Effect of ginsenosides on the desflurane modulation in the recombinant serotonin type 3A receptor expressed in Xenopus laevis oocytes / 대한마취과학회지

BACKGROUND: Postoperative nausea and vomiting (PONV) is the most frequent and discomforting side effect following general anesthesia. Most volatile anesthetics have a potent effect on serotonin (5-hydroxydtryptamine, 5-HT) type 3 receptor mediating PONV, and their antagonists have been currently used effectively to prevent and/or reduce the incidence and severity of PONV. The authors reported previously that ginsenosides have inhibitory effect on 5-HT3A receptor. In this study we intended to elucidate the inhibitory effect of ginsenosides on the potentiated 5-HT3A receptor by desflurane. METHODS: After in vitro transcription of the recombinant mouse 5-HT3A receptor in the Xenopus laevis oocyte, we examined the effects of ginsenosides (g-Rb1, g-Rg1, g-Rd, g-Rg2) as well as ginsenoside metabolite, compound K on the modulation of desflurane by measuring currents flowing through 5-HT3A receptor using two-electrode voltage clamp technique. RESULTS: Although normalized inhibitory responses of ginsenosides were same regardless of desflurane, some ginsenosides such as g-Rd, g-Rg2, and g-Rg1 showed potential inhibition to the enhanced 5-HT induced current of 5-HT3A receptor by desflurane. CONCLUSIONS: Although ginsenosides have substantial inhibitory effect on 5-HT3A receptor, the effects of ginsenoside on potentiation by desflurane of 5-HT induced current via recombinant 5HT3A receptor may depend on the types of ginsenoside, which suggesting that ginsenoside might have an antagonistic action to nausea and vomiting associated with volatile anesthetics.

Amino acid residues involved in agonist binding and its linking to channel gating, proximal to transmembrane domain of 5-HT3A receptor for halothane modulation / 대한마취과학회지

BACKGROUND: The 5-hydroxytryptamine type 3 (5-HT3) receptor is a member of the Cys-loop superfamily of ligand-gated ion channels (LGICs) and modulated by pharmacologic relevant concentrations of volatile anesthetics or n-alcohols like most receptors of LGICs. The goal of this study was to reveal whether the site-directed single mutations of E-106, F-107 and R-222 in 5-HT3 receptor may affect the anesthetic modulation of halothane known as positive modulator. METHODS: The wild-type and mutant receptors, E106D, F107Y, R222F, R222V, were expressed in Xenopus Laevis oocytes and receptor function was assessed using two electrode voltage clamp techniques. RESULTS: E106D, F107Y, R222F, R222V mutant 5-HT3A receptors were functionally expressed. F107Y mutant 5-HT3A receptors displayed decreased sensitivity to 5-HT compared to the wild type 5-HT3A receptor (P < 0.05). Halothane showed positive modulation in both wild and F107Y mutant 5-HT3A receptors but F107Y mutant 5-HT3 receptor showed greater enhancing modulation comparing to wild-type receptor. Meanwhile, R222F and R222V mutant 5-HT3 receptor lost positive modulation with 1 and 2 MAC of halothane. Most interestingly, positive modulation by halothane was converted into negative modulation in E106D mutant 5-HT3A receptor. CONCLUSIONS: The present study implicate the amino acid residues known for agonist binding and linking agonist binding to channel gating might also have important role for anesthetic modulation in 5-HT3A receptor.

Effect of scalp nerve blocks on post-craniotomy pain in the patients undergoing craniotomy

BACKGROUND: Sympathetic stimulation associated with post-craniotomy pain might subsequently increase blood pressure resulting in postoperative complications. We studied whether scalp nerve blocks would reduce the severity of postoperative pain. METHODS: Thirty-two patients undergoing craniotomy were randomly allocated to either the ropivacaine group (n = 16) or the saline group (n = 16). After the skin closure, we carried out scalp nerve blocks with ropivacaine (0.75%) or saline (0.9%). Visual analog scale scores (VAS), mean arterial pressure, and heart rate were measured at 0.5, 1, 2, 4, 6, 12, 24, and 48 h after extubation. Tramadol 50 mg iv was used as rescue analgesic. The delay before administration of the first analgesic and cumulative dose of rescue analgesic for the first 48 h postoperatively were measured. RESULTS: The ropivacaine group had lower analgesic requirements than the saline group (P = 0.008). The delay before administration of the first analgesic was not different significantly between two groups. VAS was similar between the two groups at each time interval. Postoperative MAP and HR were not significantly different between two groups. VAS did not correlate with these hemodynamic variables. CONCLUSIONS: Although scalp nerve blocks with ropivacaine reduced the analgesic requirement, they did not provide the sufficient pain relief.

The Neuromuscular Pharmacodynamics for Rocuronium at the Adductor Pollicis and the Flexor Hallucis Brevis Muscle / 대한마취과학회지

BACKGROUND: Neuromuscular block is commonly monitored using the adductor pollicis (AP) because of its easy access. However, the hand may not always be accessible for neuromuscular monitoring during surgery. In that situation, monitoring of the flexor hallucis brevis (FHB) secondary to stimulation of the tibial nerve at the ankle joint may be used as an alternative. METHODS: During propofol and remifentanil anesthesia, acceleromyography of the thumb and big toe were recorded. Single twitch responses were measured simultaneously after cumulative administration of rocuronium from 80 to 200microgram/kg at intervals of 40microgram/kg. Furthermore, the amount of rocuronium required for 50% and 95% twitch height depression were calculated. Rocuronium was infused continuously to maintain 5% to 15% twitch responses. We also obtained the onset, duration of action, and antagonism effect of neostigmine from both muscles via neostigmine (20microgram/kg) administration. RESULTS: ED50 and ED95 were significantly lower in the AP than in the FHB. The highest twitch response at peak and neostigmine antagonism were significantly higher in the FHB than in the AP. However, there was no significant difference in the onset time or duration of neostigmine between AP and FHB. CONCLUSIONS: Due to its resistance to rocuronium, the onset of FHB is not a good indicator of optimal conditions for tracheal intubation. Also, because of its higher antagonism effect, there is potential risk of overlooking a residual block. Sufficient recovery of the block should be readjusted to estimate recovery in the FHB with the use of other reliable clinical tests.