Farhad Pirouzmand

Epidemiological trends of spine and spinal cord injuries in the largest Canadian adult trauma center from 1986 to 2006

OBJECT In this study the author documents the epidemiology of spine and spinal cord injuries (SCIs) over 2 decades at the largest Level I adult trauma center in Canada. He describes the current state of spine injuries (SIs), their changing patterns over the years, and the relative distribution of different demographic factors in a defined group of trauma patients. METHODS Data on all trauma patients admitted to Sunnybrook Health Sciences Centre between 1986 and 2006 were collected from the Sunnybrook Trauma Registry Database. Aggregate data on SIs and SCIs, including demographic information, etiology, severity of injuries (injury severity score [ISS]), and associated injuries, were recorded. The data were analyzed in a main category of spinal fracture and/or dislocation with or without SI and in two subgroups of patients with SIs, one encompassing all forms of SCIs and the other including only complete SCIs (CSCIs). Collected data were evaluated using univariate techniques to depict the trend of variables over the years. The number of deaths per year and the length of stay (LOS) were used as crude measures of outcome. Several multivariate analysis techniques, including Poisson regression, were used to model the frequency of death and LOS as functions of various trauma variables. RESULTS There were 12,192 trauma patients in the study period with 23.2% having SIs, 5.4% having SCIs, and 3% having CSCIs. The SCIs constituted 23.3% of all SIs. The respective characteristics of the SI, SCI, and CSCI groups were as follows: median age 36, 33, and 30 years; median LOS 18, 27, and 29 days; median ISS 29, 30, and 34; female sex ratio 34, 24, and 23%; and case fatality rate 16.7, 16.6, and 21%. Seventy-nine percent of patients had associated head injuries; conversely, 24% of patients with head injuries had SIs. The mean admission age of patients increased by approximately 10 years over the study period, from the early 30s to the early 40s. The relative incidence of SIs remained stable at approximately 23%, but the incidence of SCIs decreased approximately 40% over time to 4.5%. Motor vehicle accidents remained the principal etiology of trauma, although falling and violence became more frequent contributors of SIs. The average annual ISS remained stable over time, but the LOS was reduced by 50% in both the SI and SCI groups. Age, ISS, and SCIs were associated with a longer LOS. The case fatality rate remained relatively unchanged over time. Poisson analysis suggested that the presence of an SCI does not change the case fatality rate. CONCLUSIONS Data in this analysis will provide useful information to guide future studies on changing SI patterns, possible etiologies, and efficient resource allocation for the management of these diseases.

Subacute femoral compressive neuropathy from iliacus compartment hematoma.

BACKGROUND Traumatic retroperitoneal hematoma in the iliacus muscle is an unusual but potentially serious cause of femoral compression neuropathy. CASE REPORT We describe the clinical, imaging, and management features of a case of traumatic iliacus retroperitoneal hematoma with delayed manifestation of femoral neuropathy. DISCUSSION The anatomical substrate for hematoma formation with subacute compression of the femoral nerve is emphasized. A subacute compartment syndrome with progressive edema, swelling and ischemia of iliacus compartment is suggested as the underlying cause. Early fasciotomy with or without hematoma evacuation should be considered in order to provide rapid decompression and to minimize the chance of permanent nerve injury.

A novel method in predicting immediate postoperative facial nerve function post acoustic neuroma excision.

Abstract: To determine whether the percentage calculated by dividing the amplitude of postexcision direct facial nerve stimulus responses (at pontomedullary junction) by the amplitude of distal ipsilateral transcutaneous (stylomastoid region) maximal stimulus responses and response amplitude progression by increasing stimulus intensities have predictive value for determining normal or near-normal (House-Brackmann Grade 1 or 2) immediate postoperative facial nerve function. Study Design: Intraoperative recordings of three muscle groups: 1) frontalis, 2) orbicularis oculi, and 3) orbicularis oris. Postexcision direct facial nerve stimulation at the pontomedullary junction and transcutaneous maximal facial nerve stimulation at the ipsilateral stylomastoid region and their associated response amplitudes were recorded. Setting: Tertiary referral center. Patients and Methods: Patients who underwent acoustic neuroma surgery from January 2004 to March 2006 with intraoperative facial nerve monitoring and an intact facial nerve after tumor excision were included. Recordings were available for 38 patients. Results: With a stimulus intensity of 0.3 mA at the root exit zone, there was an 81% positive predictive value in patients that exhibited a compound action potential of greater than 20% of maximum (sensitivity, 81%). This increased to 93% when the compound action potential was greater than 50% of maximum. When the amplitude increase was greater than 5 &mgr;V, there was a 77% positive predictive value (sensitivity, 87%). Conclusion: The percentage of the response amplitude of direct facial nerve stimulation at the pontomedullary junction when compared with the maximum response amplitude of ipsilateral transcutaneous stimulation at the stylomastoid foramen is a good predictor of normal to near-normal immediate postoperative facial nerve function. Progression of amplitude response also seems to be a good predictor of normal to near-normal immediate postoperative facial nerve function.

Epidemiological trends of traumatic optic nerve injuries in the largest Canadian adult trauma center.

BackgroundThere has been a paucity of information on the epidemiology of traumatic optic neuropathy (TON). This study documents epidemiology of TON over 2 decades in the largest level I adult trauma center in Canada. MethodsData on all the trauma patients admitted to Sunnybrook Health Sciences Centre from 1986 to 2007 were collected in a prospective database. The aggregate data on optic nerve injuries including demographic data, etiology, Injury Severity Score (ISS), and associated head and facial injuries were recorded. These were analyzed using univariate and multivariate techniques to summarize the association of different variables with TON. ResultsDuring the study period, 0.4% of all trauma patients had TON. The respective demographics for TON group were as follows: male, 76%; median for age, 33.5 years; length of hospital stay, 14 days; ISS, 32; and case fatality, 14%. About two thirds of patients with TON had associated significant head injuries. Conversely, 2.3% of patients with head injury had TON. The relative incidence of TON per year has remained variable from 0% to 1.2%. Motorized vehicle accidents remained the main etiology of TON (63%), but fall had the highest relative frequency leading to TON. In univariate analysis, both ISS and significant head injury were associated with TON. In multivariate analysis, TON was associated with only nasoethmoid complex fractures and significant head injury. ConclusionsThese data provide useful information on the frequency and etiologies of TON. It also highlights the importance of studies on better diagnostic tools for TON.

The epidemiological trends of head injury in the largest Canadian adult trauma center from 1986 to 2007.

OBJECT This study documents the epidemiology of head injury over the course of 22 years in the largest Level I adult trauma center in Canada. This information defines the current state, changing pattern, and relative distribution of demographic factors in a defined group of trauma patients. It will aid in hypothesis generation to direct etiological research, administrative resource allocation, and preventative strategies. METHODS Data on all the trauma patients treated at Sunnybrook Health Sciences Centre (SHSC) from 1986 to 2007 were collected in a consecutive, prospective fashion. The authors reviewed these data from the Sunnybrook Trauma Registry Database in a retrospective fashion. The aggregate data on head injury included demographic data, cause of injury, and Injury Severity Score (ISS). The collected data were analyzed using univariate techniques to depict the trend of variables over years. The authors used the length of stay (LOS) and number of deaths per year (case fatality rate) as crude measures of outcome. RESULTS A total of 16,678 patients were treated through the Level I trauma center at SHSC from January 1986 to December 2007. Of these, 9315 patients met the inclusion criteria (ISS > 12, head Abbreviated Injury Scale score > 0). The median age of all trauma patients was 36 years, and 69.6% were male. The median ISS of the head-injury patients was 27. The median age of this group of patients increased by 12 years over the study period. Motorized vehicle accidents accounted for the greatest number of head injuries (60.3%) although the relative percentage decreased over the study period. The median transfer time of patients sustaining a head injury was 2.58 hours, and there was an approximately 45 minute improvement over the 22-year study period. The median LOS in our center decreased from 19 to 10 days over the study period. The average case fatality rate was 17.4% over the study period. In multivariate analysis, more severe injuries were associated with increased LOS as was increasing time from injury to hospital presentation. Age and injury severity were independently predictive of mortality. CONCLUSIONS These data will provide useful information to guide future studies on the changing patterns of head injury, possible mechanisms of injury, and efficient resource allocation for management of this condition.

N. paucivorans infection presenting as a brain abscess.

We report an intracerebral abscess caused by a recently identified nocardial species, in an immunocompetent individual without extraneural involvement. A 63-year-old non-smoking Caucasian male with an unremarkable history of hypertension, presented with a 2-week history of personality changes including apathy, some difficulty walking, a tendency to veer to the left and a possible seizure. Preliminary assessment, including laboratory investigations were unremarkable. Computed tomography (CT) of his brain revealed a right frontal lobe multi-loculated, ring-enhancing lesion with vasogenic edema and associated mass effect (Figure 1). He was then referred to our institution. We found the patient afebrile, with no other focal neurological deficits. Repeat investigations including white blood cell count and chest x-ray, were normal. With a presumptive diagnosis of brain tumor, the patient was started on oral steroids and anti-seizure medication. A right frontal craniotomy was performed. Using bipolar cautery, a small corticectomy was made in the abnormal hyperemic brain surface overlying the lesion. An odorless, yellowish, creamy, pus-like discharge emanated from just underneath the cortex. Further dissection revealed a thick walled and multi-loculated cavity. Specimens were collected and the site was copiously irrigated to remove the pus-like material. The lateral ventricle was carefully avoided. Broad-spectrum coverage with ceftriaxone and metronidazole was commenced. Tissue histopathology returned consistent with Nocardia. Therefore, the antibiotics were changed to intravenous (i.v.) trimethoprim/sulfamethoxazole (TMP/SMX) and metronidazole. Metronidazole was discontinued when the anaerobic cultures returned negative. Tissue and fluid specimens were cultured on blood and chocolate agars. Gram-positive, non-hemolytic, catalase positive, weakly acid-fast, filamentous, branching bacilli were observed within 72 hours. The organism was presumptively identified as a Nocardia species. The Canadian Science Centre for Human and Animal Health confirmed it as N. paucivorans, based on 16S rDNA gene sequencing and conventional biochemical tests. Post-operatively, the patient made a rapid recovery and remained without focal deficits. The CT scan demonstrated a residual cavity behind the area of resection. Further investigations did not reveal any evidence of immunocompromise, or of nocardiosis elsewhere in the body. After a week in hospital, the patient was discharged home on i.v. TMP/SMX. Trimethoprim/sulfamethoxazole was changed to oral route when a CT, done three weeks postoperatively, showed marked attenuation of the residual abscess. Complete resolution was N. Paucivorans Infection Presenting as a Brain Abscess

Facial nerve prognostication in vestibular schwannoma surgery: The concept of percent maximum and its predictability

To evaluate percent maximum as an intraoperative facial nerve measurement for the long‐term prognostication of vestibular schwannoma surgery.

Synovial sarcoma of the brachial plexus: case report.

BACKGROUND AND IMPORTANCE Synovial sarcoma (SS) is a malignant soft-tissue tumor that rarely involves brachial plexus. The authors report a case of brachial plexus SS and review the relevant literature. CLINICAL PRESENTATION A 53-year-old woman presented with gradually enlarging right subclavicular mass over 5 years associated with sharp aching pain radiating down toward the radial 3 fingers. On examination, she had a corresponding firm mass in the supraclavicular region with a positive Tinel sign. There was no objective neurological deficit. She underwent partial excision of this mass without any further adjuvant radiation or chemotherapy. Pathology was consistent with SS. CONCLUSION Lack of any recurrence in this case 6 years after incomplete excision with no adjuvant therapy suggests slow clinical course in some of these sarcomas.

Optimal intraoperative somatosensory evoked potential stimulus intensity can be determined by nerve action potential amplitude.

Purpose: Muscle twitch threshold has been used to determine optimal stimulus intensity for somatosensory evoked potentials but neuromuscular blockade precludes the use of muscle twitch during surgery. Accordingly, nerve action potential (NAP) amplitude was investigated as a surrogate to muscle twitch. Methods: The ulnar and tibial nerves were stimulated at the wrist and ankle, respectively, in 27 patients undergoing spine and brain surgery. After neuromuscular blockade was gone, the stimulus intensity for just maximal NAP amplitude recorded from Erbs point and the popliteal fossa was compared with the stimulus intensity for hypothenar and plantar foot muscle twitch threshold (times two), respectively (Wilcoxon matched pairs test). Results: There was no significant difference between stimulus intensity for just maximal Erb’s point and popliteal fossa NAP amplitude when compared with stimulus intensity for hypothenar and plantar foot twitch threshold (times two), respectively. Eight patients required more than twitch intensity (times two) to obtain maximum NAP. Conclusions: The NAP amplitude may be used to determine optimal somatosensory evoked potential stimulus intensity when muscle twitch is not visible. This method should improve the success of intraoperative somatosensory evoked potential monitoring and decrease erroneous interpretation.

Quantitative volumetric analysis post transsphenoidal pituitary adenoma surgery.

BACKGROUND Computed tomogram (CT) imaging is often used for immediate postoperative assessment of transsphenoidal pituitary adenoma resection while magnetic resonance imaging (MRI) is used for follow-up. The residual mass is known to decrease in size over time but the difference between the two imaging modalities has not been quantified. Our objective was to quantify the size difference of the residual mass on immediate postoperative CT compared with delayed MRI. METHODS Retrospective analysis of 69 patients who had undergone pituitary adenoma resection at our institution between 2004-2010. Sellar and suprasellar diameter, along with the overall volume of the residual mass were measured on both the immediate postoperative CT and delayed MRI. RESULTS Average preoperative sellar and suprasellar diameter was 22.2 ± 4.6mm and 20.9 ± 5.9mm, respectively. Average sellar residual diameter on immediate postoperative CT (16.5 ± 5.4 mm, 25% reduction) was significantly larger than delayed MRI (10.6 ± 6.2mm, 52% reduction). The average suprasellar component on CT (15.5±6.5mm, 26% reduction) was also significantly larger than that on MRI (3.3 ± 5.4 mm, 84% reduction). The postoperative CT showed a 46% reduction in volume while a 71% reduction was noted on the delayed MRI. CONCLUSION A significant reduction in residual mass is noted on delayed MR imaging compared with immediate postoperative CT. Therefore, from a resource management and prognostication point of view, CT should be used for immediate postoperative assessment while delayed MRI should be used to assess operative success and for communication with patients.