Kim W. Johnston

Anterior Cervical Discectomy and Fusion Associated Complications

Study Design. Retrospective review study with literature review. Objective. The goal of our current study is to raise awareness on complications associated with anterior cervical discectomy and fusion (ACDF) and their early detection and proper management. Summary of Background Data. It is known that ACDF constitutes one of the most commonly performed spinal procedures. Its outcome is quite satisfactory in the majority of cases. However, occasional complications can become troublesome, and in rare circumstances, catastrophic. Although there are several case reports describing such complications, their rate of occurrence is generally underreported, and data regarding their exact incidence in large clinical series are lacking. Meticulous knowledge of potential intraoperative and postoperative ACDF-related complications is of paramount importance so as to avoid them whenever possible, as well as to successfully and safely manage them when they are inevitable. Methods. In a retrospective study, 1015 patients undergoing first-time ACDF for cervical radiculopathy and/or myelopathy due to degenerative disc disease and/or cervical spondylosis were evaluated. A standard Smith-Robinson approach was used in all our patients, while an autologous or allograft was used, with or without a plate. Operative reports, hospital and outpatient clinic charts, and radiographic studies were reviewed for procedure-related complications. Mean follow-up time was 26.4 months. Results. The mortality rate in our current series was 0.1% (1 of 1015 patients, death occurred secondary to an esophageal perforation). Our overall morbidity rate was 19.3% (196 of 1015 patients). The most common complication was the development of isolated postoperative dysphagia, which observed in 9.5% of our patients. Postoperative hematoma occurred in 5.6%, but required surgical intervention in only 2.4% of our cases. Symptomatic recurrent laryngeal nerve palsy occurred in 3.1% of our cases. Dural penetration occurred in 0.5%, esophageal perforation in 0.3%, worsening of preexisting myelopathy in 0.2%, Horner’s syndrome in 0.1%, instrumentation backout in 0.1%, and superficial wound infection in 0.1% of our cases. Conclusion. Meticulous knowledge of the ACDF-associated complications allows for their proper management. Postoperative dysphagia, hematoma, and recurrent laryngeal nerve palsy were the most common complications in our series. Management of complications was successful in the vast majority of our cases.

In vivo Proton Magnetic Resonance Spectroscopy of Brain Tumors

The ability of magnetic resonance spectroscopy (MRS) to differentiate neoplastic brain cells and their metabolic and structural characteristics is evaluated. We examined 120 patients with brain tumors using a 1.5-tesla MRI unit and MRS. The peak areas of N-acetyl-aspartate (NAA), phosphocreatine-creatine (Pcr-Cr), choline-containing compounds (Cho), lactate, lipids, myoinositol, amino acids and the ratios of NAA/Pcr-Cr, NAA/Cho and Cho/Pcr-Cr were calculated by a standard integral algorithm. In normal brain tissue, the following metabolites were identified: NAA at 2.0 ppm, Pcr-Cr at 3.0 ppm and Cho at 3.2 ppm. The different concentrations of the metabolites examined and their role in the biochemical profile of different types of tumors are discussed. The confidence interval of the MRS versus pathology was between 0.9 and 0.954, while it was between 0.52 and 0.631 for MRI versus pathology. The Cho/Pcr-Cr ratio is a very important malignancy marker for histologic tumor grading of astrocytomas. The greater this ratio, the higher the grade of the astrocytoma. NAA/Pcr-Cr together with Cho/Pcr-Cr help specify the presence or absence of a neoplasm. Proton MRS is a useful and promising diagnostic modality not only in diagnosing but also in grading solid brain tumors.

Intraventricular administration of rt-PA in patients with intraventricular hemorrhage.

Objective: Intraventricular hemorrhage (IVH) represents a clinicopathologic entity with a dismal prognosis. The associated mortality rate has been reported as high as 80%; the morbidity is also quite high. The use of various fibrinolytic agents (streptokinase, urokinase, and recombinant tissue-type plasminogen activator [rt-PA]) has been reported in a small number of clinical series with a very limited number of participants, yielding significant variability regarding inclusion criteria, treatment protocol, and outcome analysis. Methods: In our prospective study, we report our experience using rt-PA in 21 patients with IVH. Patients with IVH of aneurysmal or arteriovenous malformation origin were excluded. Intraventricular administration of rt-PA was initiated within 24 hours after the ictal event (dose, 3 mg every 24 hours) through a ventricular catheter. The patients’ intracranial and cerebral perfusion pressures, cerebrospinal fluid (CSF) cell count, and head CT scans with emphasis to frontal horn dimension and inner cranium diameter at the same level ratio were collected and analyzed. Results: Good outcome was observed in 47.5% of our patients, whereas 28.5% died and 24.0% survived with severe disability. The development of rt-PA–associated complications was as follows: new hemorrhage in 19%, infection in 14.3%, and CSF pleocytosis in 100% of patients. Permanent CSF shunt was required in 40%. The intermediate (3-month) follow up of our survivors showed no significant outcome changes compared with the immediate (1-month) follow up. Conclusions: Intraventricular administration of rt-PA appears to be beneficial in cases of IVH even though it is occasionally associated with serious complications. Further multi-institutional studies are required for validating this treatment modality and standardizing its parameters.

Correlation of the Amount of Disc Removed in a Lumbar Microdiscectomy with Long-term Outcome

Study Design. The authors conducted a prospective clinical study. Objectives. The objectives of this study were to investigate the relationship, if any, of the amount of removed disc in a standard first-time lumbar microdiscectomy and long-term outcome as well as recurrence and postoperative instability rates. Summary of Background Data. There is lack of data on the amount of disc that needs to be removed during a lumbar microdiscectomy. Anecdotal data and dogmatic recommendations make the subject even more controversial. Material and Methods. A total of 106 patients underwent a standard first-time lumbar microdiscectomy for medically refractory sciatica resulting from a herniated disc. The removed disc material was weighted. All patients were clinically followed for at least 2 years and outcome was evaluated by using pain intensity, presence of physical signs, functional capacity, return to work, and patients’ opinion regarding their outcome. Results. The mean amount of disc removed was calculated at 2.1 ± 0.9 g. Ninety-one patients had an excellent outcome and returned to their preoperative work. Fifteen patients had persistent symptomatology and underwent extensive radiographic workup, which revealed a disc recurrence at the same level in 8 patients and first-degree instability in 3 patients. In the remaining 4 patients, no clinical or radiographic abnormality was proven and the patients were treated conservatively, whereas all of them had applied for disability. No relationship was proven between the amount of the removed disc and the intraoperative blood loss or the intraoperative complication rate. Our statistical analysis showed no correlation between the amount of the removed disc and the long- term outcome, recurrence rate, or postoperative instability. Conclusions. The degree of disc removal did not influence the outcome or complication rate in our clinical series.

Cerebrospinal fluid fistula secondary to dural tear in anterior cervical discectomy and fusion: case report.

Study Design. A case of cerebrospinal fistula secondary to a dural tear during anterior cervical discectomy and fusion. Objectives. To report a quite rare complication associated with anterior cervical discectomy and remind the spinal surgeons that this infrequent complication can easily become a very serious one. Summary of Background Data. Anterior cervical discectomy represents one of the most commonly performed spinal procedures. Of the associated complications, accidental dural tear can lead to the development of a cerebrospinal fluid (CSF) fistula. Although this complication has been mentioned in several clinical series, the body of knowledge regarding incidence and appropriate treatment is definitely limited. Methods. After undergoing anterior cervical discectomy and fusion for an extruded disc at the C4–C5 level, a CSF fistula developed in a 37-year-old patient as a result of a dural tear. The patient underwent a second procedure for surgical wound revision, meticulous dural opening coverage, and insertion of a lumbar drain for draining CSF for 5 days. Results. The patient was hospitalized for 5 days and then discharged with no evidence of CSF leakage. His follow-up of 9 months revealed complete resolution of his preoperative symptomatology and no other problems associated with the complication of the CSF fistula. Conclusion. Early identification of this complication and aggressive treatment with insertion of lumbar drain, CSF drainage for 4–5 days, and coverage of the dural tear with fibrin sealant or autologous fascia graft can prevent the development of any consequences.

Quantitative Estimation of the Recurrent Laryngeal Nerve Irritation by Employing Spontaneous Intraoperative Electromyographic Monitoring During Anterior Cervical Discectomy and Fusion

Study Design Prospective, clinical study. Objective The objective of our study was to evaluate the role of laryngeal intraoperative electromyography (IEMG) in predicting the development of postoperative recurrent laryngeal nerve (RLN) palsy in patients undergoing anterior cervical discectomy and fusion (ACDF). We also attempted to develop a method to quantify the total IEMG irritation of the RLN. Summary of Background Data RLN injury has been recognized as the most common ACDF-associated neurologic injury. It has been postulated, that the employment of laryngeal IEMG may identify the operative events leading to RLN injury and subsequent postoperative palsy. Methods Laryngeal IEMG monitoring was performed in 298 patients undergoing ACDF. Preexistent baseline EMG activity, amplitude, and duration of IEMG activity were recorded. The total amount of RLN irritation was expressed as an Irritation Score (IS) applying a specially designed mathematical equation incorporating the amplitude, the duration, and the presence of any baseline EMG irritation. The relationship of IEMG activity with parameters such as the number of operative levels, the duration of the procedure, the presence of any previous neck surgeries, and the type of the used retractor was examined. Results IEMG activity was recorded in 14.4% of our patients. Postoperative RLN injury occurred in 2.3% of our patients. The sensitivity of IEMG was 100%, the specificity 87%, the positive predictive value 16%, and its negative predictive value 97%. The calculated IS ranged between 0.28 and 3.47 (mean IS: 2.09). Significantly increased IEMG activity was found in patients with previous surgical intervention, patients undergoing multilevel procedures, long-lasting procedures, and cases in which self-retained retractors were used. Likewise, significantly increased IS were observed in patients with previous surgeries and in cases where self-retained retractors were used. Conclusions Our study indicates that laryngeal IEMG is a high-sensitivity modality that can provide real-time information and can potentially minimize the risk of operative RLN injury.

Pain outcome and vertebral body height restoration in patients undergoing kyphoplasty.

Introduction: Kyphoplasty, a minimally invasive technique, has recently been developed to provide immediate pain relief, biomechanical stabilization, prevention of fracture progression, vertebral height restoration, and prevention or reversal of kyphosis to patients with osteoporotic vertebral compression fractures (VCF). Materials and Methods: We retrospectively reviewed 24 patients treated with kyphoplasty. A total of 37 vertebral levels were augmented. Visual analog scale (VAS) scores were documented in the immediate pre- and postoperative period, as well as 4, 12, and 72 weeks after the procedure. Vertebral body height restoration was assessed on postoperative x-rays. Results: Mean preoperative VAS score was 9.3 and improved to 5.4 in the immediate postoperative period. At 4, 12 and 72 weeks postoperatively, mean VAS scores were 5.1, 5.9, and 6.1 respectively. All patients returned to their daily activities within 24 hours. No significant restoration of vertebral body height was observed. Conclusion: In regards to pain relief and postoperative functional outcome, kyphoplasty is a safe and effective treatment modality for osteoporotic VCFs, even when no significant restoration of vertebral body height is achieved.

Epidural intracranial abscess as a complication of frontal sinusitis: case report and review of the literature.

Two cases of epidural abscess as a complication of frontal sinusitis are presented. The diagnoses were suspected on the basis of history and were confirmed by magnetic resonance imaging and computed tomography. Both patients were treated successfully by means of surgery and intravenous antibiotics. One patient developed meningitis in the postoperative course and was treated by changing the antibiotic regimen. However, further follow-up in the outpatient clinic by physical examinations and brain computed tomography scans showed no long-term neurologic complications in either case. Intracranial suppuration, including epidural abscesses, can complicate acute and chronic frontal sinusitis. These complications are diagnosed by maintaining a high index of suspicion and using the appropriate neuroimaging studies without delay.

Intracranial temperature: is it different throughout the brain?

AbstractIntroduction: Accurate knowledge of cerebral temperature is assuming increasing importance, because its manipulation is employed more frequently for cerebral protection. Purpose: This prospective clinical study was performed to examine how well intraventricular temperature reflects global cerebral temperature. Methods: The intraventricular temperature was monitored in 61 patients who were admitted to the neurointensive care unit for various intracranial pathological entities. A temperature probe coupled to an intraventricular pressure monitor was inserted in the lateral ventricle. At the conclusion of the monitoring process, a second intraventricular temperature probe was inserted in the ipsilateral ventricle and the previous one was carefully and gradually removed. During that removal, the intraparenchymal temperature was monitored for 90 minutes at 1-cm intervals throughout the brain parenchyma. Results: The mean intraventricular temperature was 37.84±1.03°C, whereas the mean systemic (rectal) temperature was 37.65±0.68°C. At 1 cm outward distance from the lateral ventricle, the mean intraparenchymal temperature was 38.21±0.32°C, 38.39±0.33°C at 2 cm, 38.27± 0.31°C at 3 cm, 38.26±0.29°C at 4 cm, and, finally, 37.9±0.50°C at 5 cm. Statistical analysis of the recordings showed no statistically significant differences between the intraventricular and intraparenchymal temperatures and intraventricular and rectal temperatures. No statistically significant correlation was established between the intraventricular temperature and parameters, such as the patient’s age, sex, and admitting diagnosis. Conclusion: Cerebral temperature was relatively stable through the brain parenchyma in this study. Because intraventricular temperature accurately reflects cerebral temperature, this is a reasonable monitoring site for cerebral temperature analysis.

Surgical treatment of acute type II and rostral type III odontoid fractures managed by anterior screw fixation.

Objectives: In the present study, the authors comment on their experience with anterior odontoid screw fixation in the management of odontoid fractures, in an attempt to further assess the safety and the efficacy of this procedure. Materials and Methods: A retrospective analysis of 50 consecutive patients with reducible type II or rostral type III odontoid fractures, operated at our hospital with anterior odontoid screw fixation. Radiographic bony fusion, complications, and clinical outcome were evaluated. Results: Solid bony fusion was evident in 38 (90.5%) of the patients. One mechanical instrumentation-related complication occurred, without clinical significance. No other major complications related to the procedure were noted. A satisfactory range of motion in the cervical spine was observed in all patients. Conclusions: Anterior odontoid screw fixation is a safe and effective procedure for the treatment of type II and rostral type III odontoid fractures. Compliance to the specific indications and contraindications of this operation is crucial for optimal outcome.