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Ji Hoon Phi and Chun Kee Chung

Object

Surgical treatment of brain tumors in the mesial temporal lobe (MTL) is a highly demanding procedure. Only a few studies describing the surgery of MTL tumors have been reported, and they have been focused on the operative techniques and immediate results of the surgery. The authors have analyzed the long-term oncological outcome in patients with MTL tumors.

Methods

Thirty-six patients with an MTL tumor were studied. The mean patient age at surgery was 32 years (range 13–62 years). The tumors were confined to the MTL (Schramm Type A) in 25 patients (69%). Extension of the tumor into the fusiform gyrus (Schramm Type C) and temporal stem (Schramm Type D) was observed in 4 and 7 patients (11 and 19%), respectively. There was a significant difference in the tumor size according to Schramm types (p = 0.001). Complete tumor resection was achieved in 26 patients (72%). All tumors were low-grade lesions except for 1 anaplastic astrocytoma.

Results

After a median follow-up period of 50.5 months, 7 patients showed progression of the disease. The actuarial progression-free survival rates were 97% in the 1st year, 84% in the 2nd year, and 80% in the 5th year. The degree of tumor resection was significantly related to the tumor control failure (p < 0.001) and malignant transformation of a low-grade tumor (p < 0.001). Univariate analyses using a Cox proportional hazards model showed that the following factors were significantly associated with a failure to control the tumor: 1) extent of the tumor (Schramm Type D; p = 0.003, relative risk [RR] 12.04); 2) size of the tumor (p = 0.033, RR 1.052/mm); 3) patient age at surgery ≥ 50 years (p = 0.007, RR 8.312); and 4) short duration of epilepsy (< 6 months; p = 0.001, RR 21.54).

Conclusions

Surgery is the principal treatment for MTL tumors, despite its technical difficulty. Complete tumor resection is strongly recommended for long-term tumor control. The MTL tumors are heterogeneous in their prognosis. Older age, short duration of epilepsy, and tumor size are all associated with poor outcome. Patients with these characteristics may have a more aggressive form of the disease than those with MTL tumors associated with chronic epilepsy.

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Soo Eon Lee, Chun Kee Chung and Tae Ahn Jahng

Object

The purpose of cervical total disc replacement (TDR) is to decrease the incidence of adjacent segment disease through motion preservation. Heterotopic ossification (HO) is a well-known complication after hip and knee arthroplasties. There are few reports regarding HO in patients undergoing cervical TDR, however; and the occurrence of HO and its effects on cervical motion have rarely been reported. Moreover, temporal progression of HO has not been fully addressed. One goal of this study involved determining the incidence of HO following cervical TDR, as identified from plain radiographs, and demonstrating the progression of HO during the follow-up period. A second goal consisted of determining whether segmental motion could be preserved and identifying the relationship between HO and clinical outcomes.

Methods

The authors conducted a retrospective clinical and radiological study of 28 consecutive patients who underwent cervical TDR with Mobi-C prostheses (LDR Medical) between September 2006 and October 2008. Radiological outcomes were evaluated using lateral dynamic radiographs obtained preoperatively and at 1, 3, 6, 12, and 24 months postoperatively. The occurrence of HO was interpreted on lateral radiographs using the McAfee classification. Cervical range of motion (ROM) was also measured. The visual analog scale (VAS) and Neck Disability Index (NDI) were used to evaluate clinical outcome.

Results

The mean follow-up period was 21.6 ± 7.0 months, and the mean occurrence of HO was at 8.0 ± 6.6 months postoperatively. At the last follow-up, 18 (64.3%) of 28 patients had HO: Grade I, 6 patients; Grade II, 8 patients; Grade III, 3 patients; and Grade IV, 1 patient. Heterotopic ossification progression was proportional to the duration of follow-up; HO was present in 3 (10.7%) of 28 patients at 1 month; 7 (25.0%) of 28 patients at 3 months; 11 (42.3%) of 26 patients at 6 months; 15 (62.5%) of 24 patients at 12 months; and 17 (77.3%) of 22 patients at 24 months. Cervical ROM was preserved in Grades I and II HO but was restricted in Grades III and IV HO. Clinical improvement according to the VAS and NDI was not significantly correlated with the occurrence of HO.

Conclusions

The overall incidence of HO after cervical TDR was relatively high. Moreover, HO began unexpectedly to appear early after surgery. Heterotopic ossification progression was proportional to the time that had elapsed postoperatively. Grade III or IV HO can restrict the cervical ROM and may lead to spontaneous fusion; however, the occurrence of HO did not affect clinical outcome. The results of this study indicate that a high incidence of HO with the possibility of spontaneous fusion is to be expected during long-term follow-up and should be considered before performing cervical TDR.

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Ho Jun Seol, Chun Kee Chung and Hyun Jib Kim

Object. The anterior upper thoracic spine (T1–3) is difficult to access because most neurosurgeons are unfamiliar with the anatomy. This study was performed to evaluate the different surgical options by retrospectively analyzing data on operations performed for anterior upper thoracic compression at the authors' institution.

Methods. Eighteen patients underwent surgery between November 1993 and May 2001. There were eight men and 10 women; their mean age was 55 years (range 28–80 years). All patients presented with pain and/or neurological deficits. The causes of anterior compression were diverse, although metastatic spinal tumor was most common. The approach chosen was primarily dictated by the axial involvement of the lesion. Anterior approaches, mainly the transmanubrium approach, were performed in six and posterior approaches in 12. In all cases except one, in which only an iliac bone graft was placed, instrumentation was used. The mean follow-up period was 11.4 months (range 1–57 months). One postoperative death occurred. Postoperative follow-up imaging studies, especially plain radiography, demonstrated no instrumentation failure. Improvement was shown in eight patients, an aggravation of symptoms in one, and stable clinical status in eight.

Conclusions. Decompression may be achieved on the anterior side of the upper thoracic spine if the operative approach is scrupulously chosen; this choice involves consideration of the locations of the lesion, the nature of the primary disease, and the surgery-related risk.

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Ji Hoon Phi and Chun Kee Chung

Object

Surgical treatment of brain tumors in the mesial temporal lobe (MTL) is a highly demanding procedure. Only a few studies describing the surgery of MTL tumors have been reported, and they have been focused on the operative techniques and immediate results of the surgery. The authors have analyzed the long-term oncological outcome in patients with MTL tumors.

Methods

Thirty-six patients with an MTL tumor were studied. The mean patient age at surgery was 32 years (range 13–62 years). The tumors were confined to the MTL (Schramm Type A) in 25 patients (69%). Extension of the tumor into the fusiform gyrus (Schramm Type C) and temporal stem (Schramm Type D) was observed in 4 and 7 patients (11 and 19%), respectively. There was a significant difference in the tumor size according to Schramm types (p = 0.001). Complete tumor resection was achieved in 26 patients (72%). All tumors were low-grade lesions except for 1 anaplastic astrocytoma.

Results

After a median follow-up period of 50.5 months, 7 patients showed progression of the disease. The actuarial progression-free survival rates were 97% in the 1st year, 84% in the 2nd year, and 80% in the 5th year. The degree of tumor resection was significantly related to the tumor control failure (p < 0.001) and malignant transformation of a low-grade tumor (p < 0.001). Univariate analyses using a Cox proportional hazards model showed that the following factors were significantly associated with a failure to control the tumor: 1) extent of the tumor (Schramm Type D; p = 0.003, relative risk [RR] 12.04); 2) size of the tumor (p = 0.033, RR 1.052/mm); 3) patient age at surgery ≥ 50 years (p = 0.007, RR 8.312); and 4) short duration of epilepsy (< 6 months; p = 0.001, RR 21.54).

Conclusions

Surgery is the principal treatment for MTL tumors, despite its technical difficulty. Complete tumor resection is strongly recommended for long-term tumor control. The MTL tumors are heterogeneous in their prognosis. Older age, short duration of epilepsy, and tumor size are all associated with poor outcome. Patients with these characteristics may have a more aggressive form of the disease than those with MTL tumors associated with chronic epilepsy.

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Nicholas M. Barbaro

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June Ho Lee, Chun-Kee Chung and Hyun Jib Kim

✓ A 16-year-old boy presented at the authors' emergency department with a sudden deterioration of respiration. He had been paraparetic for 3 years and had become quadriplegic 2 days previously. Magnetic resonance images revealed a Chiari I malformation and a hydromyelic cavity extending from C-1 to T-11. Rostrally, a small cylindrically shaped lesion extended from the cervicomedullary junction to the left semioval center. The patient made a dramatic neurological recovery following suboccipital craniectomy and upper cervical laminectomies with augmentation duraplasties followed by placement of a syringoperitoneal shunt.

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Woorim Jeong, Hyeongrae Lee, June Sic Kim and Chun Kee Chung

OBJECTIVE

How the brain supports intermediate-term preservation of memory in patients who have undergone unilateral medial temporal lobe resection (MTLR) has not yet been demonstrated. To understand the neural basis of episodic memory in the intermediate term after surgery for temporal lobe epilepsy (TLE), the authors investigated the relationship between the activation of the hippocampus (HIP) during successful memory encoding and individual memory capacity in patients who had undergone MTLR. They also compared hippocampal activation with other parameters, including structural volumes of the HIP, duration of illness, and age at seizure onset.

METHODS

Thirty-five adult patients who had undergone unilateral MTLR at least 1 year before recruiting and who had a favorable seizure outcome were enrolled (17 left MTLR, 18 right MTLR; mean follow-up 6.31 ± 2.72 years). All patients underwent a standardized neuropsychological examination of memory function and functional MRI scanning with a memory-encoding paradigm of words and figures. Activations of the HIP during successful memory encoding were calculated and compared with standard neuropsychological memory scores, hippocampal volumes, and other clinical variables.

RESULTS

Greater activation in the HIP contralateral to the side of the resection was related to higher postoperative memory scores and greater postoperative memory improvement than the preoperative baseline in both patient groups. Specifically, postoperative verbal memory performance was positively correlated with contralateral right hippocampal activation during word encoding in the left-sided surgery group. In contrast, postoperative visual memory performance was positively correlated with contralateral left hippocampal activation during figure encoding in the right-sided surgery group. Activation of the ipsilateral remnant HIP was not correlated with any memory scores or volumes of the HIP; however, it had a negative correlation with the seizure-onset age and positive correlation with the duration of illness in both patient groups.

CONCLUSIONS

For the first time, a neural basis that supports effective intermediate-term episodic memory after unilateral MTLR has been characterized. The results provide evidence that engagement of the HIP contralateral rather than ipsilateral to the side of resection is responsible for effective memory function in the intermediate term (> 1 year) after surgery in patients who have undergone left MTLR and right MTLR. Engagement of the material-specific contralesional HIP, verbal memory in the left-sided surgery group, and visual memory in the right-sided surgery group were observed.

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Dahye Kim, June Sic Kim, Woorim Jeong, Min-Sup Shin and Chun Kee Chung

OBJECTIVE

Mesial temporal lobe epilepsy (MTLE) surgery is associated with a risk of memory decline after surgery, but the effect of the extent and locus of temporal resection on postoperative memory function are controversial. The authors’ aim in this study was to confirm if selective resection is effective in preserving memory function and identify critical areas for specific memory decline after temporal resection.

METHODS

In this single-center retrospective study, the authors investigated data from patients who underwent unilateral MTLE surgery between 2005 and 2015. Data from 74 MTLE patients (60.8% of whom were female; mean [SD] age at surgery 32 years [8.91 years] and duration of epilepsy 16 years [9.65 years]) with histologically proven hippocampal sclerosis were included. Forty-two patients underwent left-sided surgery. The resection area was manually delineated on each patient’s postoperative T1-weighted images. Mapping was performed to see if the resected group, compared with the nonresected group, had worse postoperative memory in various memory domains, including verbal item, verbal associative, and figural memory.

RESULTS

Overall, 95.9% had a favorable epilepsy outcome. In verbal item memory, resection of the left lateral temporal area was related to postoperative decline in immediate and delayed recall scores of word lists. In verbal associative memory, resection of the anterior part of the left hippocampus, left parahippocampal area, and left lateral temporal area was related to postoperative decline in immediate recall scores of word pairs. Resection of the posterior part of the left hippocampus, left parahippocampal area, and left lateral temporal area was related to delayed recall scores of the same task. Similarly, in the figural memory, postoperative decline of immediate recall scores was associated with the resection of the anterior part of the right hippocampus, amygdala, parahippocampal area, and superior temporal area, and decline of delayed recall scores was related to resection of the posterior part of the right hippocampus and parahippocampal area.

CONCLUSIONS

Using voxel-based analysis, which accounts for the individual differences in the resection, the authors found a critical region for postoperative memory decline that is not revealed in the region-of-interest or groupwise comparison. Particularly, resection of the hippocampus was related to associative memory. In both verbal and visual memory, resection of the anterior part of the hippocampus was associated with immediate recall, and resection of the posterior part of the hippocampus was associated with delayed recall. Therefore, the authors’ results suggest that selective resection may be effective in preserving postoperative memory decline.

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Hye Seon Kim, Dong Hwan Kim, Kyung Hwan Kim, Youn Joung Cho and Chun Kee Chung

Aortic injury is a rarely encountered complication of spinal surgery. The authors report a case of a 32-year-old woman with a T3 tumor who experienced an intraoperative aortic arch injury during T3 spondylectomy. The patient was successfully treated with no postoperative neurological deficits.