Sai-Cheung Lee

Cranioplasty using polymethyl methacrylate prostheses.

In this retrospective study we attempted to assess the clinical performance of prefabricated polymethyl methacrylate (PMMA) prostheses and to determine whether they outperform intra-operatively moulded PMMA prostheses in reducing operating time, blood loss and surgical complications in elective delayed cranioplasty operations, after decompressive craniectomy, to repair large (> 100 cm2) cranial defects. Patients (n=131) were divided into three groups according to the cranioplasty technique used. Group 1 patients received fresh frozen autograft bone that had been removed at the craniectomy and refrigerated at -80 degrees C. Group 2 included patients whose PMMA prosthesis was moulded intra-operatively. Group 3 patients received a custom-made prefabricated PMMA prosthesis manufactured using computer-aided design/computer-aided manufacturing (CAD/CAM). Group 2 patients required significantly more operating time than both group 1 (p<0.001) and group 3 (p<0.001) patients, but operating time did not differ significantly between groups 1 and 3 (p>0.05). Mean intra-operative blood loss was significantly higher in group 2 than in group 1 (p=0.015) but did not differ significantly between group 1 and group 3 (p>0.05). The infection rate associated with prefabricated PMMA prostheses was lower than that for intra-operatively moulded PMMA prostheses and was comparable to that for autograft bone flaps. A CAD/CAM PMMA prosthesis is an excellent alternative when no autogenous bone graft harvested during craniectomy is available.

In situ local autograft for instrumented lower lumbar or lumbosacral posterolateral fusion

This study evaluated the effectiveness of local in situ autografts in instrumented posterolateral fusion of the lower lumbar or lumbosacral spine for treating degenerative spondylolisthesis. The subjects were 182 degenerative spondylolisthesis patients with spinal canal stenosis who, in one operation, underwent lumbar laminectomy with two-level (L3-4, L4-5 or L5-S1) transpedicle screw/rod system instrumentation and posterolateral fusion using autogenous spinous processes and laminae as the only source of bone grafts. The surgical results were assessed clinically and radiologically. All patients received follow-up for at least eighteen months. At the end of follow-up, bilateral fusion mass was radiographically confirmed in 113 (62%) patients, unilateral fusion mass was observed in fifty-seven (31%) patients, and twelve (7%) patients exhibited no fusion mass at the arthrodesis level. The clinical outcome was rated excellent/good in 138 (76%) patients, fair in thirty-five (19%) and poor in nine (5%). Use of in situ local autografts yields satisfactory clinical results in instrumented posterolateral spinal fusion. No significant correlation was noted between the level of arthrodesis and the radiological outcome, nor between the level of arthrodesis and the clinical outcome. Radiographic evaluation of bony fusion mass was not predictive of the clinical findings.

Classification of symptomatic osteoporotic compression fractures of the thoracic and lumbar spine

The pathophysiology of osteoporotic compression fractures is different from those occurring secondary to traumatic spinal injury, and currently, there is no classification suitable for symptomatic osteoporotic compression fractures treated by percutaneous vertebroplasty. We propose a new classification based on the radiological appearance in the subacute or chronic stage of the clinical presentation of these fractures. They are classified by the authors based on observations and measurements from preoperative and postoperative dynamic lateral radiographs. Compression fractures are divided into two types. Type I is a compression fracture involving the anterior column only. Type II is a fracture involving both the anterior and middle column. Each type is divided into two groups: fractures with union and those with non-union. Type II compression fractures have a higher incidence of non-union than type I (p<0.05). In both type I and II non-union groups, fractures achieve greater increase in vertebral body height after vertebroplasty than both type I and type II union group fractures (p<0.05). In both non-union groups, fractures achieved a greater reduction of kyphotic angle post-vertebroplasty than type I and II union group fractures (p<0.05). Further clinical follow-up of these patients will confirm and extend this classification.

Complications of fixation to the occiput--anatomical and design implications

Internal fixation provides an increased immediate stability for the craniovertebral junction; however, there is no current consensus on the optimal method of occipitocervical (OC) fusion. In this report, we present 25 cases of craniovertebral instability treated with OC fusion by plates and screws instrumentation. The 25 cases comprised 12 men and 13 women, whose ages ranged 20 to 78 years. The principal aetiologies that lead to the OC instability of the patients in this series included trauma, rheumatoid arthritis, neoplasm and congenital abnormality. The fusion levels ranged from occiput-C3 to occiput-C6. Two mortalities occurred. The other patients showed satisfactory union after a follow-up of eight to 24 months. OC fusion using a plates and screws system is a safe and highly effective method for providing immediate internal stability to the OC junction. The internal occipital anatomy, which cannot be seen at surgery, is important when dealing with this taxing and potentially dangerous aspect of surgery.

Continuous regional cerebral blood flow monitoring in the neurosurgical intensive care unit.

The aim of this study was to examine the intracranial pressure (ICP) and regional cerebral blood flow (rCoBF) changes during the acute stage of severe head injury and to improve outcome by modifying treatment modalities using real-time ICP and rCoBF data. Twenty patients with moderate or severe head injury that were monitored in our neurosurgical intensive care unit were included in this study. The changes in ICP, rCoBF and the relationship of ICP/rCoBF were observed. In patients with high ICP and low rCoBF, mannitol improves the rCoBF and decreases the ICP of these patients. When low rCoBF exists, hyperventilation may lead to a rapid further decline of rCoBF, however, some hyperemic brains respond well to hyperventilation treatment. Triple-H therapy is suitable for those with low rCoBF without significantly high ICP, which is an abnormal condition considered to be caused by vasospasm.

Cerebrospinal fluid galactorrhea: A rare complication of ventriculoperitoneal shunting

In this report we describe a 26-year-old woman who had an intra-abdominal pseudocyst located at the peritoneal catheter tip following ventriculo-peritoneal (VP) shunt implantation. Retrograde cerebrospinal fluid (CSF) flowed outside the catheter and communicated with the right breast lactiferous ductal system and leaked from the nipple orifice. CSF galactorrhea only occurs when the lactiferous duct is injured during VP shunt implantation, in combination with the formation of an intra-abdominal CSF pseudocyst prior to lactiferous duct healing. Leakage of CSF from the nipple orifice can be successfully treated by simply guiding the peritoneal catheter tip into the peritoneal cavity through a new laparotomy; that is, shunt revision is not always required.

Clinical experience with rigid occipitocervical fusion in the management of traumatic upper cervical spinal instability.

Traumatic injuries of the craniovertebral junction or the upper cervical spine may result in occipitocervical (OC) or upper cervical spinal instability. Internal fixation can provide immediate stability to this region. Over a 6-year period, 16 patients with traumatic upper cervical spinal instability underwent a posterior approach OC fusion, using a plate and screw system, at the neurosurgical department of our institution. One patient died. The postoperative course of all the other patients was uncomplicated. At the most recent follow-up examination, all patients had satisfactory fusion. OC fusion with a plate and screw system is a safe and effective method for the treatment of traumatic craniovertebral and high cervical spine instability. Accurate imaging diagnosis and strict patient selection are the keys to a successful outcome.

Decompressive surgery for malignant middle cerebral artery syndrome

Decompressive craniectomy has been considered the most attractive option for surgical treatment of malignant middle cerebral artery (MCA) infarction. We retrospectively reviewed the clinical and radiological records of 78 patients with malignant MCA infarction who underwent decompressive craniectomy with dura augmentation over a 6-year period. Twenty-six patients had undergone additional anterior temporal resection during decompressive craniectomy. The overall mortality at 30 days after surgery was 25.6% while the mortality rate at 6 months after surgery was 30.8%. At 6 months after surgery, 30.8% of the patients were considered to have good outcomes, while 69.2% had a poor outcome (16.7% suffered from severe disability, 21.8% remained in a vegetative state, and 30.8% died). Ipsilateral surgery was performed on 48 patients with infarction on the dominant side and on 30 patients with lesions on the non-dominant side. No significant difference was noted between these two groups at the 30-day mortality rate. Although no patient with an infarction on the dominant side recovered effective verbal ability during the 6 months of follow-up, there was no significant difference between the two groups in clinical outcome at 6 months after surgery. The 30-day survival rate in the 26 patients who underwent additional anterior temporal lobectomy was significantly higher (84.6%) than that in patients who underwent decompressive craniectomy and duroplasty only (69.2%) (p<0.05). However, in patients who survived, this additional procedure does not appear to improve the functional outcome.

Olfactory Groove Meningiomas: Surgical Experience from 35 Cases

Background: Olfactory groove meningiomas (OGMs) account for about 10% of all intracranial meningiomas. We report on the clinical outcomes and recurrence rate of OGMs after surgical treatment in our neurosurgery department. Methods: The authors searched the database at the Department of Neurosurgery, Chang Gung Memorial Hospital, Chang Gung University, Linkou for cases of OGM treated between May 1992 and September 2005. A retrospective study was conducted by analyzing the charts of the patients. The mean follow-up period was 63 mo (range, 12–178 mo). Results: Thirty-five patients underwent 39 OGM surgeries. Tumor diameter ranged from 2 to 7 cm (average, 4.8 cm). In 21 surgeries (53.8%), the tumor was removed by bifrontal craniotomy via a subfrontal approach; 6 surgeries (15.4%) involved bi-fronto-orbital craniotomy; 5 (12.8%) were accomplished by bifrontal craniotomy via an interhemispheric approach; 6 (15.4%) were performed via a unilateral subfrontal approach; and 1 (2.6%) was performed via a pterional approach. In the primary operations, total and subtotal removal were achieved in 29 (82.9%) and 6 patients (17.1%), respectively. Nine patients (25.7%) experienced surgery-related complications, the majority being 4 cases of cerebrospinal fluid leakage. There was no operative mortality and no new cases of permanent focal neurological deficit. No recurrences were reported in 31 patients (88.6%). Conclusions: Although OGMs are located at the base of the skull, a well-trained neurosurgeon can use modern microsurgical techniques with an appropriate surgical approach and obtain an excellent clinical result.

Quadriplegia secondary to cervical spondylotic myelopathy—A rare complication of head and neck surgery

Free tissue reconstruction after ablation of head and neck malignancy often requires extensive cervical manipulation, which may exacerbate preexisting cervical spondylosis and result in progression to cervical myelopathy. We present a rare case of postoperative quadriplegia caused by cervical spondylotic myelopathy after head and neck reconstruction.