Alexis retractor efficacy in transthoracic thoracoscopically assisted discectomy for thoracic disc herniations.

PURPOSE: A transthoracic anterior or lateral approach for giant thoracic disc herniations is a complex operation which requires optimal exposure and maximal visualisation. Traditional metal rigid retractors may inflict significant skin trauma especially with prolonged operative use and limit the working angles of endoscopic instrumentation at depth. We pioneer the use of the Alexis retractor in transthoracic thoracoscopically assisted discectomy for the first time. METHODS: The authors describe and demonstrate the technical use of the Alexis retractor during operative cases. Patient positioning, clinical rationale and operative nuances are elucidated for readers to gain an appreciation of the transthoracic approach to thoracic disc herniations. RESULTS: The advantages of the Alexis retractor include minimally invasive circumferential flexible retraction, facilitation of bimanual instrument use, diminished risk of surgical site infections and reduced rib retraction leading to less postoperative pain. CONCLUSION: Use of the flexible and intuitive Alexis retractor maximises operative exposure and is an effective adjunct when performing complex transthoracic approaches for thoracic disc herniations.

Survival outcomes of intracranial extraventricular neurocytomas: a systematic review and individual patient data meta-analysis.

OBJECTIVE: The rarity of intracranial extraventricular neurocytomas (EVNs) has precluded accurate definition of its surgical characteristics to date. The authors present the first survival analysis of this unique entity that aims to clarify tumor characteristics, surgical outcomes, and efficacy of postoperative adjuvant therapy. METHODS: A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Searches of the MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Database of Systematic Reviews databases were performed from inception to date. Primary outcomes were progression-free survival (PFS) and overall survival (OS). Prognostic variables were age, sex, tumor consistency, extent of resection, and receipt of postoperative adjuvant therapy. Survival data were analyzed using Kaplan-Meier survival curves and the log-rank test to compare dichotomized cohorts. Multivariate Cox regression models were constructed, interrogated with Schoenfeld residuals, and subsequently utilized to identify independent prognostic factors. Risk of bias was assessed with the Mayo Clinic instrument. RESULTS: Five hundred fourteen articles were initially retrieved, which was distilled to 10 included articles consisting of 101 cases of intracranial EVNs. The 5-year OS rate was 90.4% (95% CI 81.8%-99.8%) and the PFS rate was 48.6% (95% CI 34.46%-68.8%). The median PFS was 60 months. Patients younger than 50 years of age experienced superior OS (p = 0.03) and PFS (p < 0.01). Gross-total resection (GTR) was superior to subtotal resection (STR) in reducing mortality (p < 0.01). Adjuvant therapy following either STR or GTR did not significantly improve survival. CONCLUSIONS: Intracranial EVNs are rare tumors that portend a poorer prognosis than central neurocytomas, despite both being WHO grade 2 tumors. Complete surgical extirpation is the cornerstone of management. There is no clearly established role for adjuvant postoperative therapy, but each case should be managed on an individual basis.

Saccular posterior cerebral artery aneurysm encased within a lipoma.

We present a case of a man in his 80s with an incidental posterior cerebral artery aneurysm encased within a lipoma. The literature surrounding the incidence and intricate relationship of lipomas to cerebral aneurysms is reviewed. Lipomas are proposed to be derived from maldifferentiated subarachnoid space. For this reason, lipomas are often associated with vascular malformations and may develop in conjunction with vascular malformations such as cerebral aneurysms. Hypothesised theories include the impediment of smooth muscle nutrient diffusion and the secretion of factors that weaken the arterial wall thereby predisposing to aneurysm formation. When lipomas neighbour cerebral vasculature, careful evaluation of the adjacent vessels should be conducted.

Safety and effectiveness of spinal dural defect repair in the management of superficial siderosis: A systematic review and patient-level analysis.

OBJECTIVE: Superficial siderosis (SS) is a disabling neurodegenerative condition that may be caused by spinal dural defects. Surgical repair is increasingly performed, however clinical outcomes remain unclear. METHODS: A systematic search of PubMed, MEDLINE, and EMBASE was conducted (inception to February 2020). Studies reporting cases of (i) superficial siderosis, (ii) spinal dural defect, (iii) and surgical closure of the defect were included. Demographic characteristics, clinical presentation, operative technique and clinical outcome were extracted for patient-level analysis. RESULTS: A total of 26 publications were included, which reported 38 patients with a median age of 58 years, and a male predominance (78.9 %). Ataxia (85.7 %) and hearing loss (80.0 %) were the most common presenting symptoms. The causative dural defect was most commonly ventral in location (91.7 %) and most commonly identified by CT myelography (48.6 %). Operative technique was highly variable and included primary suture, fibrin glue, dural substitute, or tissue (fat or muscle) graft. Clinical improvement was reported in 21 %, with stabilisation of symptoms in the majority (66 %) and clinical deterioration in 13.2 %. Surgical complications were observed in 7.9 %. CONCLUSION: In patients with superficial siderosis and spinal dural defect, operative closure leads to improvement or stabilisation of symptoms in the vast majority (87%) of patients.

Prophylactic postoperative measures to minimize surgical site infections in spine surgery: systematic review and evidence summary.

BACKGROUND CONTEXT: There are three phases in prophylaxis of surgical site infections (SSI): preoperative, intraoperative and postoperative. There is lack of consensus and paucity of evidence with SSI prophylaxis in the postoperative period. PURPOSE: To systematically evaluate the literature, and provide evidence-based summaries on postoperative measures for SSI prophylaxis in spine surgery. STUDY DESIGN: Systematic review, meta-analysis, evidence synthesis. METHODS: A systematic review conforming to PRIMSA guidelines was performed utilizing PubMed (MEDLINE), EMBASE, and the Cochrane Database from inception to January 2019. The GRADE approach was used for quality appraisal and synthesis of evidence. Six postoperative care domains with associated key questions were identified. Included studies were extracted into evidence tables, data synthesized quantitatively and qualitatively, and evidence appraised per GRADE approach. RESULTS: Forty-one studies (nine RCT, 32 cohort studies) were included. In the setting of preincisional antimicrobial prophylaxis (AMP) administration, use of postoperative AMP for SSI reduction has not been found to reduce rate of SSI in lumbosacral spine surgery. Prolonged administration of AMP for more than 48 hours postoperatively does not seem to reduce the rate of SSI in decompression-only or lumbar spine fusion surgery. Utilization of wound drainage systems in lumbosacral spine and adolescent idiopathic scoliosis corrective surgery does not seem to alter the overall rate of SSI in spine surgery. Concomitant administration of AMP in the presence of a wound drain does not seem to reduce the overall rate of SSI, deep SSI, or superficial SSI in thoracolumbar fusion performed for degenerative and deformity spine pathologies, and in adolescent idiopathic scoliosis corrective surgery. Enhanced-recovery after surgery clinical pathways and infection-specific protocols do not seem to reduce rate of SSI in spine surgery. Insufficient evidence exists for other types of spine surgery not mentioned above, and also for non-AMP pharmacological measures, dressing type and duration, suture and staple management, and postoperative nutrition for SSI prophylaxis in spine surgery. CONCLUSIONS: Despite the postoperative period being key in SSI prophylaxis, the literature is sparse and without consensus on optimum postoperative care for SSI prevention in spine surgery. The current best evidence is presented with its limitations. High quality studies addressing high risk cohorts such as the elderly, obese, and diabetic populations, and for traumatic and oncological indications are urgently required.

Prospective Longitudinal Evaluation of Coagulation with Novel Thromboelastography Technology in Patients After Subarachnoid Hemorrhage: A Pilot Study.

BACKGROUND: There is limited knowledge of whether hypercoagulability is present after subarachnoid hemorrhage (SAH) or about its timing of onset, duration, and severity. To conduct a pilot new-generation thromboelastography (TEG) technology (TEG6s)-based and conventional coagulation test-supported longitudinal assessment of coagulation in patients with SAH. METHODS: We prospectively enrolled patients with nontraumatic SAH on admission from May 2015 to May 2016. We performed TEG6s measurements and conventional coagulation tests on days 1, 2, 3, 5, 7, 10, and 14 and compared them with TEG6s parameters in healthy volunteers. RESULTS: We studied 14 patients and 72 TEG6s measurements. Of these patients, 10 (71.4%) were admitted to the intensive care unit. Mean age was 57.5 (±14.5) years, Acute Physiology and Chronic Health Evaluation III score 58.2 (±26.6), length of hospital stay was 23 (±11.7) days, and mortality was 14.3%. At baseline, conventional coagulation tests were within normal range. However, TEG6s parameters already showed increased coagulability. Thereafter, alpha angle, reaction time, functional fibrinogen level, and maximum amplitude rapidly and significantly increased (P < 0.01) compared with healthy controls. Ten (71.4%) patients demonstrated a >20% increase in coagulability based on TEG6s parameters from their baseline. Moreover, TEG6s hypercoagulability peaked at day 10 and only showed an initial partial decline towards normal by day 14. Similarly, platelet counts and fibrinogen levels increased over this period (P < 0.01) CONCLUSIONS: Using TEG6s technology, we found significant and progressive hypercoagulability in 70% of patients, with an early dominant contribution from hyperfibrinogenemia and increased fibrin formation and partial contribution from thrombocytosis, beginning on the first day, increasing to peak values by day 10, and then partly declining toward normal by day 14.

Anterior versus posterior approach in traumatic thoracolumbar burst fractures deemed for surgical management: Systematic review and meta-analysis.

Uncertainties remain regarding the optimal surgical approach in the treatment of traumatic thoracolumbar burst fractures. We aim to compare the surgical, radiological and functional outcomes in anterior versus posterior approaches in patients with traumatic thoracolumbar burst fractures deemed for surgical management. A systematic review adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed. Qualitative analysis and where suitable, meta-analysis were performed to compute pooled estimates of the differences between anterior and posterior approaches. A total of six studies (three observational, one prospective non-randomized trial, two randomized controlled trials) were included. There were no cases of postoperative neurological decline. Meta-analysis demonstrates a longer duration (Mean Difference (MD) + 81.68, 95% CI 39.20 to 123.16, p < 0.001) and increased estimated blood loss (MD + 426.27, 95% CI 119.84 to 732.70, p = 0.006) for the anterior approach. No difference between approaches was found regarding length of hospital stay, late postoperative kyphotic angle, construct failure rate, instrumentation revision rate, rate of return to work, and total hospital charges. Limitations include the small number of, and heterogeneity across studies. Given the similarities in neurological, radiological and functional outcomes between the two approaches, the longer duration and estimated blood loss in the anterior approach should be a point of consideration when selecting the surgical approach. There is an urgent need for contemporary, high quality research in this area.

A single-institution prospective evaluation of a neuro-oncology multidisciplinary team meeting.

Multi-disciplinary team meetings (MDTs) are considered essential to quality cancer care. For some malignancies, MDTs have been associated with improved outcomes, but data regarding the neuro-oncology MDT is limited. We prospectively described the MDT at our institution and evaluated its impact on clinical management. Cases were discussed amongst the treating team and a pre-MDT plan and reason for discussion (RFD) was documented before the MDT. Patient specific clinical data was captured prospectively, with further pathological and radiological information captured during the MDT. Subsequently, the MDT consensus decision was recorded. High impact decisions (HID) were those in which the pre-MDT plan was substantially modified. A HID rate of >10% was considered clinically significant. Adherence to MDT recommendations was recorded. Seventy-nine cases were discussed at the MDT. Fifty-two cases (66%) were male. The median age was 53 (17-84). Thirty-three cases were new diagnoses and the remainder were relapsed/progressive disease. Thirty-nine cases were primary brain tumours, 25 were metastatic tumours and 15 were other. Twenty-eight (35%) had HID. No RFDs were statistically significantly associated with a HID (p = 0.265). Adherence data was collected for 95% (75) of cases. Treatment concordance with the MDT plan occurred in 90% (67) of cases. For cases of non-concordance, six out of eight (75%) were due to patient choice. Overall, a clinically significant proportion of treatment modifications are made at the neuro-oncology MDT. There were no case types which did not benefit from MDT discussion. MDT recommendations were largely adhered to, and in cases of non-concordance, were largely due to patient choice.

Radiological evaluation of C1 pedicle screw anatomic feasibility.

C1 pedicle screw instrumentation is a recently documented technique, which may have benefits over other more popularised procedures, however it may not be possible in all patients. This study aims to investigate the applicability of the C1 pedicle screw technique to a cohort of patients through assessment of radiological parameters. A retrospective review of 150 consecutive patients undergoing computer tomography (CT) of the cervical spine was performed. Based on defined parameters images were assessed for feasibility of placement of pedicle screws. C1 pedicle height (PH), pedicle width (PW), screw trajectory length (LML) and width (LMW) were recorded with PH  ≥ 4 mm defined as the primary outcome measure. A total of 115 patients and 230 C1 pedicles were examined. The mean PH was found to be 5.1 mm. 207 pedicles were deemed suitable for placement of pedicle screw instrumentation. Overall C1 pedicle screw instrumentation was deemed possible in 94.6% of male pedicles and 84% of female pedicles. C1 pedicle screw instrumentation is feasible to be performed in more than 90% of the patients.

Case report: Angiosarcoma of the cervical spine.

Angiosarcomas (ASs) are rare malignant vascular tumours, which only occasionally occur in the spine. The prognosis is generally poor due to rarity of the condition as well as lack of data of treatment options. We present the case of a 75-year old man with a primary angiosarcoma of C2 and C3 who underwent occipito-cervical (to C6) fixation. A first biopsy did not result in a diagnosis and a further anterior approach with repeat biopsy had to be undertaken. The patient received adjuvant radiotherapy and at 6-month follow-up there was no radiological progression of the angiosarcoma. ASs are a rare condition and due to paucity of data relating to management cases should be reported to aid understanding and development of guidelines for diagnosis and treatment.

Congenital biparietal foramina presenting with multiple concussions.

We report a man with biparietal foramina secondary to Potocki-Shaffer syndrome. This is due to incomplete ossification of parietal bones secondary to haploinsuffiency of ALX4 gene. He presented with multiple episodes of concussion following minimal head trauma. Cranioplasty was performed to close the skull defects with the aim of preventing further concussion and permanent traumatic brain injury.

Correlation between pedicle size and the rate of pedicle screw misplacement in the treatment of thoracic fractures: Can we predict how difficult the task will be?

STUDY DESIGN: A retrospective study. OBJECTIVE: To correlate the incidence of pedicle-screw (PS) misplacement with the dimensions of the pedicles in the treatment of thoracic spine fractures. SUMMARY OF BACKGROUND DATA: The technical challenge of internal fixation with PS in the thoracic spine has been well documented in the literature. However, there are no publications that document the correlation between the pedicle dimensions of the thoracic vertebrae in the preoperative computed tomography scans (CT) and the rate of PS misplacement. METHODS: All patients who had PSs inserted between the T1 and T12 vertebrae during a 24-month period were included in this study. PS position was assessed on high quality CT scans by two independent observers and classified in 2 categories: correct or misplaced. The transverse diameter, craniocaudal diameter and cross-sectional area of the pedicles from T1 to T12 were measured in the pre-operative CT. RESULTS: During the period of this study 36 patients underwent internal fixation with 218 PS. Of the 218 screws, 184 (84.5%) were correct and 34 (15.5%) were misplaced. Misplacement rate was 33% for pedicles with a transverse diameter less than 5 mm, 10.7% for those with a transverse diameter between 5 and 7 mm and 0% for those with a transverse diameter larger than 7 mm. There was a statistically significant difference in the rate of PS misplacement in pedicles with transverse diameter smaller than 5 mm compared with the others. Also, those with transverse diameter between 5.1 and 7 mm compared with those bigger than 7 mm in diameter. The rate of PS misplacement was higher between T3 and T9 (p < 0.05), which in turn correlated with pedicle transverse diameter. CONCLUSION: The rate of PS misplacement in the mid thoracic spine (T4-T9) is high and correlates with pedicle transverse diameter.

Radiation induced malignant peripheral nerve sheath tumour of the second cervical nerve.

We report a 44-year-old with progressive quadriparesis due to a dumbbell malignant peripheral nerve sheath tumour (MPNST) of the second cervical nerve, 17 years after whole brain radiotherapy for a pineal germinoma. To our knowledge this is the first case of radiation induced high cervical MPNST arising from a benign neurofibroma.

Lymphoma of the trigeminal nerve--the need for histological diagnosis.

CNS lymphoma involving the trigeminal nerve is a rare condition which presents as a cavernous sinus lesion. It may mimic the radiological appearance of other lesions, and biopsy is essential before considering empirical radiotherapy for lesions in this region. We report the radiological, histopathological and operative findings of a primary non Hodgkin B cell lymphoma involving the trigeminal nerve.

An in vivo mouse model of intraosseous spinal cancer causing evolving paraplegia.

The spine is the commonest site of skeletal metastatic disease and uncontrolled growth of cancer in the spine will inevitably cause pain and neurologic compromise. Improved understanding of the pathobiology behind this devastating condition is urgently needed. For this reason, the aim of this study was to establish a clinically relevant, animal model of spinal cancer. A percutaneous orthotopic injection of human breast (MDA-MB-231) or human prostate (PC-3) cancer cells was administered into the upper lumbar spine of nude mice (n = 6). Animals were monitored twice daily for general welfare, gait asymmetry or disturbance, and hindlimb weakness. After sacrifice, plain radiographs, micro-CT imaging and histological analysis of the spines were performed on each mouse. All mice recovered fully from the inoculation procedure and displayed normal gait and behaviour patterns for at least 3 weeks post-inoculation. Subsequently, between 3 and 5 weeks post-inoculation, each mouse developed evolving paralysis in their hindlimbs over 48-72 h. All followed the same pattern of decline following onset of neurological dysfunction; from gait asymmetry and unilateral hindlimb weakness, to complete unilateral hindlimb paralysis and finally to complete bilateral hindlimb paralysis. Plain radiographs, micro-CT scanning and histological analysis confirmed local tumour growth and destruction of the spine in all six mice. An in vivo mouse model of human intraosseous spinal cancer has been established forming cancers that grow within the spine and cause epidural spinal cord compression, resulting in a reproducible, evolving neurological deficit and paralysis that closely resembles the human condition.

Single-level/single-stage debridement and posterior instrumented fusion in the treatment of spontaneous pyogenic osteomyelitis/discitis: long-term functional outcome and health-related quality of life.

STUDY DESIGN: Retrospective study. OBJECTIVE: To support single-level posterior debridement and instrumented interbody fusion as a single-stage procedure for spontaneous pyogenic osteomyelitis/discitis. SUMMARY OF BACKGROUND DATA: The best surgical technique for patients with bacterial spinal infections is still a matter of debate. Recent publications suggest that titanium implants can be used safely in the infectious sites in combination with debridement and antibiotic therapy. METHODS: We retrospectively review patients with spontaneous pyogenic osteomyelitis/discitis in whom medical therapy failed, and they consequently underwent posterior decompression and instrumented fusion. Data was collected regarding demographics, clinical presentation, images and laboratory studies, antibiotic treatment, duration of hospitalization, time to achieve radiologic evidence of fusion, postoperative complications, and neurologic function pre- and postoperatively. Quality of life was measured using the EQ5D questionnaire and level of disability with the Oswestry Disability Index. RESULTS: Nine patients, ranging in age from 41 to79 years, with a Frankel score of D in 7 cases and of E in 2 cases, underwent a single-level/single-stage debridement and posterior instrumented fusion with pedicle screws and an interbody and posterolateral autogenous bone graft. Preoperative neurologic deficits improved in all the cases and solid bone fusion was achieved in all 9 patients at 12 months. The mean follow-up period was 67 months. The infection healed after surgery in all the patients and they did not require a second operation to remove the metal implants. Quality of life assessed with the EQ5D questionnaire showed scores ranging between 0.70 and 1. The median Oswestry Disability Index was 15.5%. CONCLUSIONS: These findings support that debridement and posterior instrumented fusion can be performed as a single-stage procedure with no increase in the recurrence rate or morbidity. The outcome has been satisfactory in our patients in terms of the rate of fusion and quality of life.