[Microvascular Decompression for Trigeminal Neuralgia Due to Venous Compression].

In microvascular decompression surgery for trigeminal neuralgia, the veins are essential as an anatomical frame for the microsurgical approach and as an offending vessel to compress the trigeminal nerve. Thorough arachnoid dissection of the superior petrosal vein and its tributaries provides surgical corridors to the trigeminal nerve root and enables the mobilization of the bridging, brainstem, and deep cerebellar veins. It is necessary to protect the trigeminal nerve by coagulating and cutting the offending vein. We reviewed the clinical features of trigeminal neuralgia caused by venous decompression and its outcomes after microvascular decompression. Among patients with trigeminal neuralgia, 4%-14% have sole venous compression. Atypical or type 2 trigeminal neuralgia may occur in 60%-80% of cases of sole venous compression. Three-dimensional MR cisternography and CT venography can help in detecting the offending vein. The transverse pontine vein is the common offending vein. The surgical cure and recurrence rates of trigeminal neuralgia with venous compression are 64%-75% and 23%, respectively. Sole venous compression is a unique form of trigeminal neuralgia. Its clinical characteristics differ from those of trigeminal neuralgia caused by arterial compression. Surgical procedures to resolve venous compression include nuances in safely handling venous structures.

Exoscopic microvascular decompression for hemifacial spasm and trigeminal neuralgia.

The 4K 3D exoscope system is becoming increasingly used in neurosurgery. Its 3D ultra-high-definition image is valuable in identifying and dissecting the delicate neural and vascular structures during microvascular decompression. In this video, the authors describe several nuances and details to perform the exoscopic microvascular decompression, including the exoscope layout and the modified supine position. Several illustrative case presentations highlight the benefits of exoscopic surgery. The authors' exoscopic microvascular decompression series of 159 patients showed noninferior surgical outcomes compared to the operative microscope with no significant increase in surgical risk. In conclusion, an exoscope can be a practical alternative to performing microvascular decompression. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23122.

Risk of Bone Wax Migration During Retrosigmoid Craniotomy for Microvascular Decompression: Case-Control Study.

BACKGROUND AND OBJECTIVES: Bone wax is a flexible hemostatic agent commonly used for surgery in the posterior cranial fossa to control bleeding from the mastoid emissary vein. A large amount of bone wax can migrate into the sigmoid sinus through the mastoid emissary canal (MEC). We aimed to identify clinical factors related to intraoperative bone wax migration through the MEC during microvascular decompression (MVD) surgery, which may result in sigmoid sinus thrombosis. METHODS: We retrospectively collected the clinical data of patients with trigeminal neuralgia, hemifacial spasm, or trigeminal neuralgia accompanied by painful tic convulsif who underwent MVD. Basic information and the residual width and length (from the bone surface to the sigmoid sinus) of the MEC on computed tomography images were collected. We compared the collected clinical data between 2 groups of cases with and without intraoperative bone wax migration in the sigmoid sinus. RESULTS: Fifty-four cases with intraoperative bone wax migration and 187 patients without migration were enrolled. The t -test revealed significant differences in the width and length of the MEC ( P = .013 and P = .003, respectively). These variables were identified as significant factors in predicting intraoperative bone wax migration using multivariate logistic regression analysis. CONCLUSION: The large size of the MEC may be related to intraoperative bone wax migration into the sigmoid sinus in MVD. Neurosurgeons should be aware of these risks. Bone wax should be applied appropriately and hemostasis should be considered to control bleeding from the mastoid emissary vein in patients with a large MEC.

Low back pain improvement after cervical laminoplasty in patients without tandem lumbar stenosis.

PURPOSE: This study aimed to demonstrate the impact of lumbar spinal stenosis (LSS) on LBP after cervical laminoplasty for cervical spinal stenosis by analyzing the clinical characteristics and surgical outcomes. METHODS: This retrospective cohort study analyzed 56 consecutive patients with cervical spinal stenosis who underwent cervical laminoplasty. Data on age, sex, Japanese Orthopaedic Association (JOA) scores, JOA Back Pain Evaluation Questionnaire (BPEQ), and visual analog scale (VAS) were collected. The patients with VAS for LBP ≥ 30 or more were included and divided into two groups: without LSS [LSS (-)]or with LSS [LSS (+)]. Preoperative clinical characteristics and postoperative changes were compared between the groups. RESULTS: Preoperative VAS for LBP were 50.7 ± 16.2 mm and 59.8 ± 19.5 mm in the LSS (+) and LSS (-), respectively (p = 0.09). Patients in the LSS (-) were younger (57.6 ± 11.2 vs. 70.7 ± 8.6, p < 0.001) and showed significantly milder preoperative lumbar symptoms in terms of JOA and BPEQ. Patients in the LSS (-) group showed more postoperative changes in low back pain (18.3 ± 26.4 vs. - 8.3 ± 37.6, p = 0.005) and lumbar function (10.8 ± 25.7 vs. - 2.0 ± 22.5, p = 0.04) at BPEQ, and higher recovery in terms of VAS of LBP (23.0 ± 23.8 mm vs. 5.3 ± 25.9 mm, p = 0.008) and buttocks and low limbs (12.5 ± 35.0 mm vs. - 4.3 ± 24.4 mm, p = 0.029). Nine patients in the LSS (+) group underwent lumbar surgery at 12.8 ± 8.5 months after cervical laminoplasty. CONCLUSION: LBP improved after cervical laminoplasty in patients without lumbar stenosis.

Functionality and Usability of the Exoscope in Microvascular Decompression for Hemifacial Spasm and Trigeminal Neuralgia.

BACKGROUND: Studies on the functionality and usability of the exoscope in neurosurgical procedures against surgical microscopes (SMs) are limited. This study aimed to examine the functionality and usability of the exoscope during microvascular decompression (MVD) surgery. METHODS: Seven neurosurgeons evaluated the usefulness of a 4 K, 3-dimension digital exoscope in MVD by answering a questionnaire. The questionnaire inquired about the functionality and usability of the exoscope by utilizing a visual analog scale (VAS; 1-10). A score of 5 on VAS was equivalent to the corresponding quality of the SM. The learning effect of the exoscope was evaluated using mean VAS scores in the first and last 3 cases for each neurosurgeon. RESULTS: The functionality of the exoscope in MVD was superior to that in SM (P < 0.001). In the last 3 surgeries, the mean VAS scores of the exoscope were excellent in terms of ease of arm handling, exchange of surgical instruments, ease of surgical procedure, and intraoperative physical stress. The mean VAS scores of the exoscope in intraoperative asthenopia were significantly higher than those of the SM (P < 0.001). No statistical significance was found in operation time, discharge outcome, and 1-year post-surgery outcome between MVD performed using the exoscope and SM. CONCLUSIONS: Neurosurgeons may experience reduced stress levels during MVD when using the exoscope. As the outcome of MVD using the exoscope did not demonstrate a statistical difference compared with MVD using the SM, the exoscope may prove to be a useful tool for performing MVD.

Postoperative vasospasm and cerebral infarction in a patient with large pituitary adenoma and cerebral superficial siderosis.

Background: Cerebral vasospasm and infarction are rare complications of transsphenoidal surgery for pituitary adenoma. Cerebral superficial siderosis may result from subarachnoid hemorrhage from a pituitary adenoma. The constellation of cerebral superficial siderosis, cerebral vasospasm, and pituitary adenoma is rare. We describe an extremely rare clinical constellation of immediately postoperative cerebral vasospasm and consequent cerebral infarction in a case with a large pituitary adenoma and cerebral superficial siderosis. Case Description: A 70-year-old man presented with a pituitary adenoma causing a worsening headache. Preoperative magnetic resonance (MR) images revealed cerebral superficial siderosis, suggesting subarachnoid hemorrhage from pituitary apoplexy. MR angiography (MRA) showed no vasospasm. During the transsphenoidal surgery, an intratumoral hematoma was found. The arachnoid membrane was partially torn and intratumoral hematoma entered the subarachnoid space. Intraoperatively, the intracranial vessels remained intact. The suprasellar tumor was almost entirely resected; however, the patient remained comatose postoperatively. Computed tomography revealed ischemic lesions in the bilateral insular and frontotemporal cortex. MRA revealed cerebral vasospasm in the bilateral middle cerebral arteries. The patient was treated with levetiracetam for nonconvulsive status epilepticus and underwent a lumbar peritoneal shunt surgery for secondary hydrocephalus. However, the patient remained listless. Conclusion: Postoperative cerebral vasospasm and infarction are severe but rare complications for a pituitary adenoma after transsphenoidal surgery. Preoperative and intraoperative subarachnoid hemorrhage might have been a risk factor in our case. Similar cases should be warranted to analyze whether cerebral superficial siderosis may also indicate the risk of severe postoperative vasospasm immediately after transsphenoidal surgery for pituitary adenoma.

Intramedullary feeder aneurysm of a cervical epidural arteriovenous fistula causing myelopathy: a case report and literature review.

While a craniocervical junction (CCJ) epidural arteriovenous fistula (EDAVF) may present with hemorrhagic myelopathy from an associated feeder aneurysm on rare occasions, non-hemorrhagic myelopathy from such an aneurysm remains unreported. A woman in her late sixties presented with cervical myelopathy due to a non-hemorrhagic intramedullary aneurysm associated with CCJ-EDAVF. The intramedullary aneurysm originated from the spinal pial artery supplied by the anterior spinal artery. Direct surgical fistula coagulation and feeder obliteration resulted in the disappearance of the aneurysm and myelopathy improvement. This report illustrates the first case of a non-hemorrhagic intramedullary aneurysm associated with CCJ-EDAVF successfully treated with direct surgery.

Cone-beam CT-assisted microcatheter tip placement at the shunted pouch entry zone: A technical note for anterior condylar arteriovenous fistula.

Accurate microcatheter placement for anterior condylar arteriovenous fistula (AVF) enables selective transvenous embolization (TVE) and helps to avoid hypoglossal nerve palsy. Anterior condylar AVF has a shunted pouch within the condylar vascular and osseous structures. Detailed anatomical comprehension of the shunted pouch is essential, in addition, we believe that it is important to have a strategy for where in the shunted pouch to start filling with coils. Specifically, we consider that it is important to structurally understand the more upstream location (arterial side) within the shunted pouch (called "shunted pouch entry zone"), guide the microcatheter there, and embolize from that site. Although several studies have discussed the usefulness of intraoperative cone-beam computed tomography (CBCT) for treating anterior condylar AVF, there are no studies which have mentioned the importance of microcatheter position before coil embolization in selective TVE as in this study. Intraoperative localization of the shunted pouch entry zone is often difficult. Herein, the authors report that cone-beam computed tomography (CBCT) can assist accurate microcatheter tip placement at the shunted pouch entry zone before staring embolization. This is the novel application of intraoperative CBCT to treat anterior condylar AVF successfully treated with precise and selective TVE.

Infratentorial developmental venous anomaly concurrent with a cavernoma and dural arteriovenous fistula.

OBJECTIVES: While developmental venous anomaly (DVA) may be associated with cavernous malformation, mixed vascular malformation associated with dural arteriovenous fistula (dAVF) has not been previously reported. We observed a case with rare association of infratentorial DVA, cavernous malformation, and dAVF that presented with cerebellar ataxia. We report our endovascular treatment for this complex cerebrovascular condition. CASE PRESENTATION: A 32-year-old woman with ataxia had an infratentorial DVA associated with a cavernoma and dAVF. The dAVF had two shunting points. The dAVF was fed by the posterior meningeal arteries and drained through the sigmoid sinus into the transverse sinus. The dAVF was also fed by the occipital artery and retrogradely drained through the left jugular bulb into the dilated collecting vein of the DVA. Endovascular embolization was performed for the dAVF and dilated collecting vein of the DVA. Postoperative complications did not occur after embolization with no recurrence for three years. CONCLUSIONS: This is the first reported case of infratentorial DVA associated with a cavernoma and dAVF. Endovascular treatment was effective in treating this symptomatic complex cerebrovascular disorder.

Carotid Micromesh Stent for the Cervical Carotid Artery Dissecting Aneurysm in a Patient with Vascular Eagle Syndrome.

OBJECTIVES: An elongated styloid process may cause vascular Eagle syndrome that includes cervical carotid artery (CCA) dissection with stenosis and aneurysm formation. There are only four reported cases with vascular Eagle syndrome-related CCA dissecting aneurysm treated with carotid artery stenting (CAS). This is the first report of applying a dual-layer nitinol micromesh stent (CASPER) for vascular Eagle syndrome-related CCA dissecting aneurysm. CASE PRESENTATION: A 38-year-old man presented with a sudden onset of aphasia and right hemiplegia. Cerebral angiography demonstrated the left CCA dissecting aneurysm. The superior trunk of the left middle cerebral artery (MCA) was also occluded, and emergent thrombectomy was performed. Computed tomography with angiography (CTA) revealed that a 33 mm-long styloid process compressed the CCA at the aneurysm formation. Three weeks later, a CASPER stent was applied for the CCA aneurysm under the flow reversal system. Immediately after stent placement, blood flow in the aneurysm became stagnant, and postoperative CTA demonstrated regression of the aneurysm. The aneurysm did not recur for 6 months with no styloid process resection. CONCLUSIONS: The dual-layer nitinol micromesh stent (CASPER) was useful to treat vascular Eagle syndrome-related CCA dissecting aneurysm.

Interactive spinal computed tomography angiography-guided spinal digital subtraction angiography and embolization for thoracolumbar epidural arteriovenous fistulas: illustrative case.

BACKGROUND: Spinal digital subtraction angiography (sDSA) is the gold standard for examining spinal arteriovenous fistulas; however, thorough sDSA evaluations of spinal arteriovenous fistulas require a long procedure, which may increase the radiation exposure time. OBSERVATIONS: A 72-year-old man presented with progressive myelopathy due to a spinal epidural arteriovenous fistula. Spinal computed tomography angiography (sCTA) showed an epidural arteriovenous fistula fed by the left L3 segmental artery. To prepare for sDSA, the sCTA images were modified to mark the segmental artery bifurcations from T5 to L5 with multicolored markers. These modified sCTA images were loaded onto the multiwindow DSA display. The sCTA images were interactively modulated during sDSA. This sCTA-guided sDSA identified 18 segmental arteries within 47 minutes. The total radiation exposure was 1,292 mGy. Subsequently, transarterial embolization resolved the epidural arteriovenous fistula with clinical improvement. LESSONS: Three-dimensional sCTA can provide detailed anatomical information before sDSA. Modified sCTA images with segmental artery bifurcation marking can provide interactive guidance on multipanel DSA displays. sCTA-guided sDSA is useful for accurate catheterization and reduction of procedure time.

Nervus Intermedius Section to Mobilize the Anterior Inferior Cerebellar Artery in Microvascular Decompression Surgery for Hemifacial Spasm: A Technical Case Report.

BACKGROUND: The course of the anterior inferior cerebellar artery (AICA) in the cerebellopontine angle may affect the technical options in microvascular decompression surgery for hemifacial spasm. A complex relationship between the AICA and the nervus intermedius has rarely been discussed in patients with hemifacial spasms. CASE DESCRIPTION: A 74-year-old woman presented with left facial spasms for 8 years. Intraoperative endoscopic observation confirmed that the left nervus intermedius crossed over the left AICA and limited its mobilization from the root exit zone (REZ) of the left facial nerve. Nervus intermedius section enabled mobilization of the AICA to decompress the facial nerve REZ. Her hemifacial spasm was resolved completely after the surgery with no significant complication. CONCLUSIONS: The AICA may be found between the nervus intermedius and the facial nerve proper in patients with hemifacial spasm. Endoscope can visualize the relationship between the AICA and the nervus intermedius. Nervus intermedius section is a useful option in case that the nervus intermedius limits adequate mobilization of the AICA from the facial nerve REZ.

Extradural Anterior Clinoidectomy and Optic Canal Unroofing for Paraclinoid and Basilar Aneurysms: Usefulness of a No-Drill Instrumental Method.

The authors describe extradural anterior clinoidectomy without the use of a high-speed drill or ultrasonic device to clip paraclinoid and basilar aneurysms, which can eliminate potential complications related to traditional power drilling or ultrasonic device use. This method involves four steps: (1) partial osteotomy of the sphenoid wing at the superior orbital fissure (SOF); (2) peeling of the dura propria of the temporal lobe from the inner cavernous membrane of the SOF; (3) isolation and resection of the exposed meningo-orbital band to expose the superolateral aspect of the anterior clinoid process (ACP); and (4) piecemeal rongeuring of ACP and the roof of the optic canal. The entire procedure was performed using surgical instruments, including micro-rongeurs, a fine Kerrison punch, and micro-dissectors. Subsequently, intradural neck clipping was performed. Twenty consecutive patients with paraclinoid and basilar aneurysms successfully underwent clipping after this non-drill extradural clinoidectomy. Minor morbidity was noted in two patients (cerebrospinal fluid leakage in one and transient oculomotor palsy in the other). The non-drill method is a simple, easy, safe, and quick alternative to traditional power drilling in extradural clinoidectomy, and this method can avoid morbidity related to direct mechanical/thermal injury of important neurovascular structures.

Bridging veins and veins of the brainstem in microvascular decompression surgery for trigeminal neuralgia and hemifacial spasm.

OBJECTIVE In microvascular decompression surgery for trigeminal neuralgia and hemifacial spasm, the bridging veins are dissected to provide the surgical corridors, and the veins of the brainstem may be mobilized in cases of venous compression. Strategy and technique in dissecting these veins may affect the surgical outcome. The authors investigated solutions for minimizing venous complications and reviewed the outcome for venous decompression. METHODS The authors retrospectively reviewed their surgical series of microvascular decompression for trigeminal neuralgia and hemifacial spasm in patients treated between 2005 and 2017. Surgical strategies included preservation of the superior petrosal vein and its tributaries, thorough dissection of the arachnoid sleeve that enveloped these veins, cutting of the inferior petrosal vein over the lower cranial nerves, and mobilization or cutting of the veins of the brainstem that compressed the nerve roots. The authors summarized the patient characteristics, operative findings, and postoperative outcomes according to the vascular compression types as follows: artery alone, artery and vein, and vein alone. They analyzed the data using chi-square and 1-way ANOVA tests. RESULTS The cohort was composed of 121 patients with trigeminal neuralgia and 205 patients with hemifacial spasm. The superior petrosal vein and its tributaries were preserved with no serious complications in all patients with trigeminal neuralgia. Venous compression alone and arterial and venous compressions were observed in 4% and 22%, respectively, of the patients with trigeminal neuralgia, and in 1% and 2%, respectively, of those with hemifacial spasm (p < 0.0001). In patients with trigeminal neuralgia, 35% of those with artery and venous compressions and 80% of those with venous compression alone had atypical neuralgia (p = 0.015). The surgical cure and recurrence rates of trigeminal neuralgias with venous compression were 60% and 20%, respectively, and with arterial and venous compressions the rates were 92% and 12%, respectively (p < 0.0001, p = 0.04). In patients with hemifacial spasm who had arterial and venous compressions, their recurrence rate was 60%, and that was significantly higher compared to other compression types (p = 0.0008). CONCLUSIONS Dissection of the arachnoid sleeve that envelops the superior petrosal vein may help to reduce venous complications in surgery for trigeminal neuralgia. Venous compression may correlate with worse prognosis even with thorough decompression, in both trigeminal neuralgia and hemifacial spasm.

[Treatment of Non-Traumatic Spinal Epidural Hematoma:A Report of Five Cases and a Systematic Review of the Literature].

Objective:Non-traumatic spinal epidural hematoma(SEH)is relatively rare. We report five cases of SEH, review the relevant literature, and discuss the current treatment strategies for non-traumatic SEH in Japan. Methods:Clinical data of cases with non-traumatic SEH treated at our institute from 2008 to 2015 were retrospectively analyzed. In addition, we identified the relevant literature using the Japan Medical Abstracts Society databases for peer-reviewed articles published from Jan 1, 1995 to Aug 31, 2015. The search terms "spinal", "epidural hematoma", and "non-traumatic OR spontaneous" were used. Treatment strategies were summarized according to the treatment criteria. Results:Five patients(1 man and 4 women;age, 59-86 years;mean age, 74 years)were treated for SEH. Hematomas were located in the cervical(n=1), cervicothoracic(n=2), thoracic(n=1), and thoracolumbar(n=1)regions. All patients suffered sudden neck and/or back pain followed by subsequent neurological deterioration. Four patients were under antithrombotic treatment, and underwent laminectomy and drainage of the hematoma due to severe and progressive neurological deficits. All patients demonstrated significant neurological recovery. Seventy-seven articles from domestic institutes and hospitals were identified. Their criteria for conservative and surgical treatments differed based on the time from the onset and severity. Conclusion:Five cases of non-traumatic SEH were treated successfully. Patients with moderate to severe neurological deficit need timely surgical management, while non-surgical treatment may be indicated in mild deficits. To standardize the optimal treatment for non-traumatic SEH, an appropriate assessment system incorporating the time from onset and severity of neurological impairment should be established.

[A Single-Stage Combined Supra- and Infra-Sellar Approach for Recurrent Large Pituitary Adenomas:Report of Two Cases].

Despite the recent technological advances in operative instruments and development of novel techniques for endoscopic skull-base surgeries, surgical treatment of primary or recurrent large/giant pituitary adenomas remains a challenge. Postoperative hemorrhage from the residual tumor and the associated impairment of the adjacent cranial nerve functions can cause severe morbidity. To manage such operative risks, a combined supra- and infra-sellar approach(CSISA)can be used as a surgical option for difficult-to-resect large/giant pituitary adenomas. We successfully performed a single-stage CSISA in two patients with large recurrent pituitary adenomas with favorable outcomes. Both patients had recurrent adenomas after multiple trans-sphenoidal surgeries and presented with visual impairment due to tumor regrowth. Each tumor had a maximum diameter of more than 4 cm. One tumor extended into the anterior skull base, while the other extended into the supra-sellar region with extremely lateral invasion. The CSISA helped surgeons visualize the tumors and the surrounding structures through a combination of different operative views. Subtotal resection was safely achieved in both cases, with no postoperative hemorrhage and deterioration of visual and pituitary function. The CSISA is useful not only for pituitary adenomas with anterior or lateral extension and multi-lobular growth, but also for certain cases with recurrent large/giant pituitary adenomas.

Autologous clavicle bone graft for anterior cervical discectomy and fusion with titanium interbody cage.

A variety of donor-site complications have been reported for anterior cervical discectomy and fusion (ACDF) using autologous iliac bone graft. To minimize such morbidities and to obtain optimal bony fusion at the ACDF surgery, a novel technique was used to harvest cancellous bone from the autologous clavicle instead of the popular iliac crest graft. After a routine cervical discectomy of the affected level, a 1.5-cm linear skin incision was made over the clavicle within 2.5 cm of the sternoclavicular joint on the medial one-third portion. This portion is known as an anatomically safe zone, with no subcutaneous distribution of the supraclavicular nerve. Then, cancellous bone was harvested through a small cortical window developed on the clavicle. Care was taken not to injure the subclavian major vessels and the lung below the clavicle. A box-type titanium cage was packed with the harvested cancellous bone and then inserted into the discectomy-treated space for cervical interbody fusion. From 2009 to 2013, 16 patients with cervical radiculopathy and/or myelopathy underwent single-level ACDF with this method. All but 1 patient experienced significant improvement of clinical symptoms after the surgery and showed radiographic evidence of solid bony fusion and spinal stabilization within 6 months. Further, no peri- and postoperative complications at the clavicular donor site were noted. The mean visual analog scale pain score (range 0 [no pain to 10 [maximum pain]) at 1 year after the surgery was 0.1, and 13 of 14 patients with data at 1-year follow-up were highly satisfied with their donor-site cosmetic outcome. The clavicle is a safe, reliable, and technically easy source of autologous bone graft that yields optimal fusion rates and patient satisfaction with ACDF surgery.

Intramedullary spinal cord abscess and subsequent granuloma formation: a rare complication of vertebral osteomyelitis detected by diffusion-weighted magnetic resonance imaging.

An intramedullary spinal cord abscess, which is usually associated with discitis, is an uncommon but potentially important complication of vertebral osteomyelitis. The authors describe a rare case of an intramedullary conus medullaris abscess and lumbar osteomyelitis sparing the intervertebral discs and without discitis. The patient also developed a granuloma in the cauda equina during treatment. Diffusion-weighted MRI was useful for differentiating the granulomatous lesion from the relapse of infection. A 65-year-old immunocompetent man with moderately controlled diabetes presented with progressive lowerextremity numbness and weakness with urinary dysfunction. He had progressive paraparesis, bilateral leg paresthesia, and sphincter compromise. Magnetic resonance imaging revealed an intramedullary ring-enhanced lesion, which was hyperintense on diffusion-weighted images. The lesion, an intramedullary spinal cord abscess, was surgically drained. During antibiotic treatment, serial MRI showed an enlarging enhanced lesion in the cauda equina, and a recurrent infection was suspected. A second-look surgery confirmed the formation of a granuloma and the absence of a relapse of the abscess. Although the enhanced lesion increased in size, its intensity on diffusion-weighted images remained unchanged. After 3 months of antibiotic treatment, all enhanced lesions were diminished. An intramedullary spinal cord abscess is a rare but important complication of vertebral osteomyelitis, and it requires immediate treatment. Diffusion-weighted MRI was useful for the initial diagnosis as well as for monitoring treatment efficacy.