Relationship between herniated intervertebral disc fragment weight and pain in lumbar microdiscectomy patients.

OBJECTIVE: The relationship between lumbar disc herniation (LDH) size and the severity of preoperative pain and its impact on postoperative recovery is incompletely understood. This study was conducted to investigate the association between herniated disc fragment weight and pain before and after microdiscectomy. METHODS: A consecutive series of patients from an ongoing randomised controlled trial (ACTRN12616001360404) were included in this study. Included patients were aged between 18 and 75, had a clinical diagnosis of radiculopathy, and MRI evidence of a concordant single-level lumbar disc herniation. All patients underwent standard microdiscectomy without aggressive discectomy or curettage of the endplates. Disc fragment weight was measured intraoperatively. RESULTS: A total of 122 patients with a mean age of 49.5 ± 12.8 years, were included. The median weight of disc fragment was 0.545 g (95% CI 0.364 - 0.654 g). There was no relationship between disc weight and the duration of symptoms (p = 0.409) severity of preoperative leg pain (p = 0.070) or preoperative back pain (p = 0.884). Disc fragment weight was demonstrated to have no correlation with clinically significant postoperative leg pain improvement (p = 0.535) or back pain (p = 0.991). Additional LDH factors, including radiological percentage of canal compromise (p = 0.714), herniation classification (p = 0.462), and vertebral level (p = 0.788) were also shown to have no effect on leg pain outcomes. CONCLUSIONS: Disc fragment weight had no effect on the severity of pain at presentation or after microdiscectomy. Patients benefit from surgery equally, regardless of the size of LDH.

Extended maxillotomy for skull base access in contemporary management of chordomas: Rationale and technical aspect.

Minimally invasive approaches to the central skull base have been popularized over the last decade and have to a large extent displaced 'open' procedures. However, traditional skull base surgery still has its role especially when dealing with a large clival chordoma where maximal surgical resection is the principal goal to maximize patient survival. In this paper, we present a case of a 25year-old male patient with chordoma in the inferior clivus which was initially debulked via a transnasal endoscopic approach. He unfortunately had a large recurrence of tumor requiring re-do resection. With the aim to achieve maximal surgical resection, we then chose the technique of a transoral approach with Le Fort 1 maxillotomy and midline palatal split. Post-operative course for the patient was uneventful and post-operative MRI confirmed significant debulking of the clival lesion. The technique employed for the surgical procedure is presented here in detail as is our experience over two decades using this technique for tumors, inflammatory lesions and congenital abnormalities at the cranio-cervical junction.

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.

Prevalence of adjacent segment disc degeneration in patients undergoing anterior cervical discectomy and fusion based on pre-operative MRI findings.

Anterior cervical discectomy and fusion (ACDF) is a widely accepted surgical treatment for symptomatic cervical spondylosis. Some patients develop symptomatic adjacent segment degeneration, occasionally requiring further treatment. The cause and prevalence of adjacent segment degeneration and disease is unclear at present. Proponents for motion preserving surgery such as disc arthroplasty argue that this technique may decrease the "strain" on adjacent discs and thus decrease the incidence of symptomatic adjacent segment degeneration. The purpose of this study was to assess the pre-operative prevalence of adjacent segment degeneration in patients undergoing ACDF. A database review of three surgeons' practice was carried out to identify patients who had undergone a one- or two-level ACDF for degenerative disc disease. Patients were excluded if they were operated on for recent trauma, had an inflammatory arthropathy (for example, rheumatoid arthritis), or had previous spine surgery. The pre-operative MRI of each patient was reviewed and graded using a standardised methodology. One hundred and six patient MRI studies were reviewed. All patients showed some evidence of intervertebral disc degeneration adjacent to the planned operative segment(s). Increased severity of disc degeneration was associated with increased age and operative level, but was not associated with sagittal alignment. Disc degeneration was more common at levels adjacent to the surgical level than at non-adjacent segments, and was more severe at the superior adjacent level compared with the inferior adjacent level. These findings support the theory that adjacent segment degeneration following ACDF is due in part to the natural history of cervical spondylosis.

The learning curve of pedicle screw placement: how many screws are enough?

STUDY DESIGN: A retrospective study. OBJECTIVE: Assess the learning curve of pedicle screw (PS) placement of a Spinal Surgery Fellow (SSF) with no previous experience with the technique. SUMMARY OF BACKGROUND DATA: Recent studies have attempted to identify the learning curve for different surgical procedures to define training requirements. Several authors have described a learning curve for PS placement. However, no one has defined the number of PS necessary to be competent in this skill. METHODS: All patients who had PS inserted by the SSF under the supervision of an Attending Spinal Consultant (ASC) and had adequate postoperative radiographs and computed tomography scans available, were included in this study. PS position was assessed by 2 blinded independent observers using a grading scale. PS placement by the SSF was evaluated by examining the assessed position in chronological groups of 40 screws. RESULTS.: Ninety-four patients underwent internal fixation of the spine with 582 PS. Eight cases (40 screws) were excluded because of lack of imaging studies. Of the 542 screws under evaluation, 320 (59%) were performed by the SSF, 187 (34.5%) by the ASC, and 35 (6.5%) by advanced orthopedic or neurosurgical trainees.The rate of misplaced PS performed by the SSF for the first 80 PS was 12.5% and dropped to 3.4% for the remaining 240 screws, which is a statistically significant difference (P < 0.01). Evaluation of computed tomography of vertebrae with PS placed by the SSF on one side and by the ASC on the other showed that the ASC achieved better placement during the first 80 PS (P < 0.01). However, this difference disappeared in the last 240 (P = 1.00). CONCLUSION: The findings demonstrate a learning curve for PS placement. In this series, the asymptote for this technique for an inexperienced SSF, started after about 80 screws (approximately 25 cases).