Tonsillar herniation as a complication of lumboperitoneal shunt: case report and literature review.

Tonsillar herniation is a rare and seldom reported complication after lumboperitoneal (LP) shunting. There have been only few reports that have presented possible options for treatment with varying degrees of success. In this report, we describe a rare case of tonsillar herniation after LP shunting and review related literature.A 17-year-old girl with hydrocephalus related to a traumatic brain injury underwent implantation of an adjustable pressure shunt (valve setting2.5) and a small lumen peritoneal catheter via the L4-L5 interspinal space. One month later, she was admitted to the emergency room with a Glasgow Coma Scale score ofE1M1Vt and dilated pupil. Image studies demonstrated new-onset tonsillar herniation and a mild cervical syrinx. Emergent suboccipital decompressive craniectomy, C1 laminectomy, and duraplasty were performed. This was followed with ligation of the LP shunt and implantation of a ventriculoperitoneal (VP) shunt a few days later. The patient's Glasgow Coma Scale score gradually recovered to 6, which was her previous neurologic status.Tonsillar herniation as a complication after LP shunting is best treated with decompression, ligation or removal of the LP shunt, and a shift to a VP shunt. The tonsillar herniation should be rapidly addressed to avoid persistent symptoms or progression of the neurologic deficits.

1.5T versus 3T MRI for targeting subthalamic nucleus for deep brain stimulation.

BACKGROUND: Accurate stereotactic placement of the electrode into the subthalamic nucleus (STN) is imperative to the therapeutic efficacy of deep brain stimulation (DBS). However, it is not always possible to directly visualize the very small STN using 1.5T MR imaging. OBJECTIVE: To evaluate whether 3T MR imaging can provide better identification of the STN and clinical outcome than 1.5T MR imaging. METHODS: Thirty-nine patients with advanced Parkinson's disease underwent 1.5T (n = 16) or 3T (n = 23) fast spin echo T2-weighted (FSE-T2WI) MR imaging for targeting the STN. A semi-quantitative 3-point scoring system was proposed to rank the clearness of STN contour: Score "0" if non-visible; Score "1" if visible but with blurred margin; and "2" if visible with clear margin. The unified Parkinson's disease rating scale (UPDRS) was also compared before operation and post-operation. RESULTS: The STN score was 2 in all the patients of the 3T group, whereas it was relatively blurred (mean score, 1.19) in the 1.5T group (P < 0.001). The number of microelectrode trajectories (1.2 versus 1.5; P < 0.05) was lower in the 3T group; consequently, the operative time was also less (P < 0.05) as compared with that in the 1.5T group. The outcome of UPDRS motor examination showed no significant difference in two groups. CONCLUSION: 3T MR imaging is a reliable and more accurate method for direct targeting of the STN for DBS surgery. However, the technique of high-sequence MR imaging may not influence the clinical outcome significantly.

Severe pneumocranium after gamma knife stereotactic radiosurgery for brain metastasis: A case report and literature review.

RATIONALE: Gamma knife stereotactic radiosurgery (GKRS) is a recognized safe and effective treatment for brain metastasis; however, some complications can present significant clinical challenges. This case report highlights a rare occurrence of cerebrospinal fluid (CSF) leakage and pneumocranium following GKRS, emphasizing the need for awareness and prompt management of these complications. PATIENT CONCERNS: A 35-year-old male with a history of malignant neoplasm of the lip in 2015 and perineural spread of malignancy into the left cavernous sinus was treated with GKRS in 2017. The patient was admitted emergently 39 days after discharge due to persistent headache and dizziness. DIAGNOSES: Brain computed tomography (CT) revealed diffuse bilateral pneumocranium alongside an observation of CSF leakage. INTERVENTIONS: A surgical procedure involving a left frontal-temporal craniotomy was performed to excise a residual skull base tumor and repair the dura, guided by a navigator system. The conclusive pathological assessment revealed the presence of squamous cell carcinoma markers. OUTCOMES: The patient exhibited excellent tolerance to the entire procedure and experienced a prompt and uneventful recovery process. After surgery, the symptoms alleviated and CSF leak stopped. The follow-up image showed the pneumocranium resolved. LESSONS: Pneumocranium due to early-stage post-GKRS is uncommon. The rapid tumor shrinkage and timing of brain metastasis spreading through the dura can lead to CSF leak and pneumocranium. We reviewed current treatment options and presented a successful craniotomy-based dura repair case.

Minimally Invasive Resection of a Foraminal Lumbar Root Schwannoma.

Background and Importance: This video article reports a rare case of a right L5/S1 foraminal root schwannoma that presents the natural course of the disease, imaging findings, treatment protocol, operative procedure, and highlights some of the possible surgical complications. Clinical Presentation: Magnetic resonance imaging (MRI) revealed an intradural, extramedullary, well-enhanced mass at the right L5/S1 level. The operative procedure involved a right minimal L5/S1 laminotomy/foraminotomy posteriorly to open the right L5 root. The facet joints were preserved to prevent spinal instability. The tumor was located along the root after opening the right L5/S1 foramen. Intraoperative electromyography (IOM) was conducted to detect any nerve injury in the patient. After opening the dura, the tumor was carefully separated from the normal root nerve under IOM monitoring. The mass was removed piece-by-piece using mini-forceps. Conclusion: Histopathological examination confirmed the diagnosis of a schwannoma. The patient recovered without incident after surgery with minimal soreness and numbness in the right leg.

Reversible hypothalamic dysfunction in optic nerve germinoma.

Primary optic apparatus germ cell tumors are rare. There have been only 6 cases reported in the literature. Although they often disturb the hypothalamus-pituitary-adrenal axis and cause progressive visual loss, the influence of treatment outcomes on hypothalamic autoregulation has never been mentioned. Here, we report a patient with an optic nerve germinoma who presented with reversible visual and hypothalamic dysfunction, and we discuss the possible mechanisms and pathogenesis.

Continuous intrathecal saline infusion for treating refractory spontaneous intracranial hypotension: A case report.

Spontaneous intracranial hypotension (SIH) is a poorly understood condition that presents with a wide variety of symptoms, ranging from mild headaches to coma. It is typically caused by continuous spontaneous leakage of spinal cerebrospinal fluid (CSF), resulting in orthostatic headaches. However, the appropriate management of refractory SIH remains unclear. A 50-year-old man presented with orthostatic headache followed by a rapid decline in mental status. The imaging findings were consistent with the diagnosis of SIH, with bilateral cerebral subdural hematomas and abnormal fluid collection in the posterior epidural space from the T2 to T12 levels. Computed tomography myelography of the whole spine revealed multiple high-flow CSF leakages at the T6 to T8 levels. Despite treatment with bilateral burr hole drainage for subdural hematomas and repeated lumbar epidural blood patch (EBP) three times, the patient's condition worsened and he developed stupor. A lumbar intrathecal saline bolus (90 ml) was administered to restore CSF depletion. The patient's verbal function improved immediately, and continuous intrathecal saline infusion was administered at a rate of 10 ml/h for two days. The patient's stupor gradually resolved, and after his symptoms improved, the EBP injection was repeated at the T8 level. The patient recovered completely, and during the six-year follow-up, there were no signs of recurrence. SIH may cause a refractory decline in mental status, and lumbar intrathecal saline infusion may help arrest or reverse an impending central (transtentorial) herniation. This case demonstrates an appropriate bolus and continuous infusion of normal saline, and documents the resolution of SIH. This maneuver may change the CSF flow pattern and aims to seal the CSF fistula. Further studies are needed to better understand the mechanism of intrathecal saline infusion and establish effective treatment strategies for refractory cases of SIH.

Clinical Outcome and Safety of Lumboperitoneal Shunt in the Treatment of Non-Obstructive Hydrocephalus.

Objective: This study aimed to evaluate the functional outcomes of lumboperitoneal (LP) shunt for the treatment of non-obstructive hydrocephalus. Methods: We retrospectively studied the clinical surgical results of 172 adult patients with hydrocephalus who underwent LP shunt surgery between June 2014 and June 2019. Data regarding the following were collected: pre- and postoperative symptom status, third ventricle width changes, Evans index, and postoperative complications. Additionally, the baseline and follow-up Glasgow Coma Scale (GCS) score, Glasgow Outcome Scale (GOS), and Modified Rankin Scale (mRS) scores were investigated. All patients were followed up for ≥12 months using clinical interview and braining imaging using computed tomography (CT) scan or magnetic resonance imaging (MRI). Results: Majority of patients presented with normal pressure hydrocephalus as the etiology of their disease (48.8%), followed by cardiovascular accident (28.5%), trauma (19.7%), and brain tumor (3%). The mean GCS, GOS, and mRS improved postoperatively. The average period from symptomatic onset to surgery was 402 days. The average width of the third ventricle on CT scan or MRI was 11.43 mm preoperatively and 10.8 mm postoperatively (P<0.001). The Evans index improved from 0.258 to 0.222 after operation. The symptomatic improvement score was 7.0, with a complication rate of 7%. Conclusion: Significant improvement was observed in the functional score and brain image after LP shunt placement. Moreover, the satisfaction with symptomatic improvement after surgery remains high. LP shunt operation is a viable alternative in the treatment of non-obstructive hydrocephalus due to the low complication rate, fast recovery, and high satisfaction.

Capability of identifying red nuclei in different pulse sequences of regular 1.5-tesla magnetic resonance images.

OBJECTIVE: To investigate the optimal pulse sequences of commonly used 1.5-tesla MRI for identifying the red nucleus (RN) to aid targeting of the subthalamic nucleus (STN). METHODS: Forty-six healthy adults were enrolled for this prospective study. All subjects underwent MR studies of 5 sequences: diffusion-weighted imaging (DWI), T(1)-weighted fluid-attenuated inversion recovery (T1IR), fast spin echo T(2)-weighted imaging (FSE-T2WI), T(2)-weighted fluid-attenuated inversion recovery (T2FLAIR) and T(2)*-weighted gradient-echo (T2*-GRE) sequences. The clearness of the RN contour was analyzed. RESULTS: Overall, the RN was identified in 98% subjects without gender and age differences. The RN was demarcated on a 5-mm slice relatively better in T2FLAIR (93.5%), followed by FSE-T2WI (78.3%), T2*-GRE (65.2%) and DWI (43.5%) sequences, but was completely invisible on the T1IR image. Generally, the signal intensity in all MR sequences decreased mildly on 2-mm slices with a similar identifying power. The detecting power on 5-mm slices was in favor of T2FLAIR with 94% sensitivity, 10% specificity, and 1.89 odds ratio compared to FSE-T2WI. In addition, the scanning time of T2FLAIR was longer in comparison to the FSE-T2WI study. CONCLUSION: T2FLAIR is an alternative to FSE-T2WI that can readily demarcate the RN to help target the STN.

Intradural lumbar disc herniation: A case report and literature review.

Study design and objection: Intradural disc herniation is a unusual disease associated with spinal surgery. The definitive diagnosis of intradural herniation depends on intraoperative findings. Summary of background data: We present the case of a 63-year-old woman with backache and left sciatica radiation for more than two months. The L2/3 laminectomy and discectomy were performed after magnetic resonance imaging (MRI) study; however, no disc rupture was noted during surgery. Follow-up lumbar spine MRI revealed one large, ruptured disc. The patient underwent revision surgery with durotomy. The large intradural disc was found and removed piece by piece. Methods Results and Conclusions: Intradural disc herniation, especially large herniation, is hard to diagnose specifically despite the progression of neuroradiologic imaging techniques. A durotomy procedure should be considered if there is a missing ruptured disc or a palpable intradural mass during surgery.

Patient-derived tumor organoids as a platform of precision treatment for malignant brain tumors.

Malignant brain tumors consist of malignancies originated primarily within the brain and the metastatic lesions disseminated from other organs. In spite of intensive studies, malignant brain tumors remain to be a medical challenge. Patient-derived organoid (PDO) can recapitulate the biological features of the primary tumor it was derived from and has emerged as a promising drug-screening model for precision therapy. Here we show a proof-of-concept based on early clinical study entailing the organoids derived from the surgically resected tumors of 26 patients with advanced malignant brain tumors enrolled during December 2020 to October 2021. The tumors included nine glioma patients, one malignant meningioma, one primary lymphoma patient, and 15 brain metastases. The primary tumor sites of the metastases included five from the lungs, three from the breasts, two from the ovaries, two from the colon, one from the testis, one of melanoma origin, and one of chondrosarcoma. Out of the 26 tissues, 13 (50%) organoids were successfully generated with a culture time of about 2 weeks. Among these patients, three were further pursued to have the organoids derived from their tumor tissues tested for the sensitivity to different therapeutic drugs in parallel to their clinical care. Our results showed that the therapeutic effects observed by the organoid models were consistent to the responses of these patients to their treatments. Our study suggests that PDO can recapitulate patient responses in the clinic with high potential of implementation in personalized medicine of malignant brain tumors.

Preventing iatrogenic injury from inadvertent intracranial migration of a urinary foley catheter while controlling profuse epistaxis after severe craniofacial trauma.

The massive nasopharyngeal bleeding that may accompany complicated comminuted fractures of the craniofacial bones can be controlled by pressure tamponade using an inflatable urinary Foley catheter. However, inadvertent intracranial catheter penetration poses a serious risk in such situations. Management of a relevant case is described, and a simple preventive measure is suggested.

Tension Pneumoventricle After Endoscopic Transsphenoidal Surgery for Rathke Cleft Cyst.

BACKGROUND: Tension pneumoventricle is an extremely rare, but treatable, neurosurgical emergency. The prompt and accurate diagnosis of tension pneumoventricle requires vigilance for the detection of clinical signs, which should also be corroborated by the imaging findings. We have reported on the pathophysiology of tension pneumoventricle and its management. CASE DESCRIPTION: A 66-year-old woman had presented with a Rathke cleft cyst. The patient underwent transsphenoidal surgery (TSS), with no clinical cerebrospinal fluid leakage observed peri- or postoperatively. However, she developed an altered mental status 8 hours after surgery, and a computed tomography scan showed evidence of a tension pneumoventricle. The patient underwent emergent external ventricular drainage insertion and exploratory endoscopic TSS. A 1-way valve was observed during TSS, and the sella floor was packed with a fat graft for 1-way valve obliteration. The patient recovered well without neurologic deficits. No radiologic regrowth was noted at the 48-month follow-up examination. CONCLUSIONS: Tension pneumoventricle is an extremely rare, but life-threatening, complication of TSS. The development of tension pneumoventricle should be kept in mind even when the surgery has proceeded very smoothly. Sellar reconstruction will, theoretically, prevent this extremely rare complication but might increase the recurrence rate of Rathke cleft cysts. The related symptoms and signs should be recognized. Prompt recognition and treatment of this condition can be life-saving, and the long-term outcomes have generally been favorable if the condition has been recognized early.

Focal conformal fractionated radiotherapy vs. radiosurgery for lung cancer patients with limited brain metastases.

BACKGROUND: For lung cancer (LC) patients with limited brain metastases (LBM), radiosurgery (RS) was the current preferred strategy. We aimed to report our experience regarding an alternative strategy (focal conformal fractionated radiotherapy, FCFRT) for these patients in this cohort study. METHODS: We identified LC patients with LBM treated with either FCFRT or RS within 2016-2019 without prior brain local treatment via in-house databases. The characteristics of patients, disease, treatment, and outcome were retrospectively obtained via chart review and peer review. The 1st day of FCFRT or RS was the index date. Overall survival (OS) was calculated from the index date to the last date of contact or death via the Kaplan-Meier method. Log-rank test was used in univariate analyses (UVA) whereas Cox regression method was used in the multivariate analyses (MVA). The incidence of local progression (LP) or distal brain metastases (DBM) was estimated by the competing risk approach with death as the competing risk. RESULTS: We identified 23 eligible patients. The median dose/fractionation for FCFRT was 36 Gy/10 fractions. The median dose for RS was 20 Gy. The Lung-molGPA prognostic groups' distribution for these two groups was not statistically different. After a median follow-up of 8 months (range, 1-38 months), the OS was not statistically different in UVA [P value 0.9]. The adjusted hazard ratio of death was 0.96 when FCFRT was compared to RS in MVA (95% CI, 0.21-5.22). There was also no statistical significant difference in LP (P value 0.79) or DBM (P value 0.88). CONCLUSIONS: For LC patients with LBM, the OS was not statistically different for definitive FCFRT or RS. There was also no statistical difference in LP or DBM. Further studies should be considered to clarify the indication of FCFRT.

Sciatica caused by pseudomyxoma peritonei.

Many etiologies may cause sciatica, and intra-abdominal masses usually affect the lumbosacral plexus by local invasion or distal metastases. Lumbosacral plexopathy caused by compression of intra-abdominal tumors instead of invasion is rarely seen. A 67-year-old woman had a 3-month history of progressive neurogenic claudication, lumbago and left L5 radiculopathy with foot drop. Nocturia and progressive abdominal distension with voiding dysfunction were also noted. Imaging studies showed a huge pelvic mass with severe compression of the left lumbosacral trunk. There was no direct invasion of the lumbosacral plexus by the pelvic mass noted in the preoperative imaging studies or intraoperative findings. Bilateral ovarian borderline mucinous cystic tumor with pseudomyxoma peritonei (PMP) was diagnosed, and the sciatica was improved dramatically after subsequent abdominal debulking surgery. Although rare, neural compression caused by PMP and intra-abdominal masses needs to be considered in the differential diagnosis of sciatica.

Three-dimensional reconstructed CT scanning for targeting hypertensive putaminal hemorrhage.

We developed an accurate frontal targeting method for hypertensive putaminal hemorrhage (HPH) using three-dimensional (3D) reconstructed CT scanning. Five consecutive unconscious patients with a significant volume of HPH were treated neuroendoscopically via frontal trephination. CT images were examined and reconstructed by an independent neuroradiologist for measuring the selected frontal entry point, depth of penetrating path, and surgical trajectory on the basis of the plane formed by the bilateral orbitomental lines delineated on the reconstructed 3D CT images. All patients regained consciousness post-operatively without complications. All had an accurate trajectory of penetrating path and the average percentage hematoma evacuation was 84%. Use of the 3D reconstructed CT imaging technique combined with neuroendoscopy may prove valuable as a minimally invasive and time-saving method of targeting HPH. Using this method, no further CT scanning is needed for subsequent surgical planning.

Change of cervical balance following single to multi-level interbody fusion with cage.

Postoperative limitation of cervical movement and adjacent disc degeneration are major causes of postoperative neck pain after anterior cervical discectomy and interbody fusion (ACDF). We present a retrospective study of dynamic radiographic change following ACDF with cages. We performed ACDF in 50 patients with cervical degenerative diseases, divided into three groups based on the level of interbody fusion (Group A: one-level; Group B: two-level; Group C: three-level). Preoperative and postoperative flexion-extension X-rays were acquired and cervical range of motion (ROM), lordosis, fusion rate, cage subsidence rate, postoperative neck pain as evaluated by visual analogue scale (VAS) and upper adjacent level segmental movement were evaluated. The average following time was 14.6 months. The mean change in lordotic curve was -2.31 +/- 9.53 degrees for Group A, 5.60 +/- 6.96 degrees for Group B, and 3.23 +/- 7.50 degrees for Group C (p value = 0.03). The mean change in flexion angle was -5.46 +/- 8.69 degrees for Group A, -10.2 +/- 7.38 degrees for Group B, and -13.86 +/- 10.33 degrees for Group C (p value = 0.039). The mean change in total cervical ROM was -3.85 +/- 18.74 degrees for Group A, -12.73 +/- 10.31 degrees for Group B, and -16.95 +/- 10.57 degrees for Group C (p value = 0.02). Follow-up cervical MRI for patients with persistent neck pain showed no evidence of adjacent level degeneration. There were no significant differences between the three groups with respect to postoperative change in cervical extension angle, upper adjacent level segmental movement, neck pain VAS, fusion rate or cage subsidence rate. The further decrease in total cervical ROM and flexion movement after multi-level ACDF was observed. However, a more long-term follow-up was needed to assess the actual aetiologies of upper adjacent level degeneration.

Burr hole drainage for complicated spontaneous intracranial hypotension syndrome.

Spontaneous intracranial hypotension is a potentially severe condition that is caused by continuous cerebrospinal fluid leakage. Clinically, most patients have a benign course and the condition remits after conservative management. We report two consecutive patients who presented with acute expansion of subdural collection and disturbed consciousness. Both patients recovered completely after undergoing burr hole drainage.

Surgical results of cranioplasty using three-dimensional printing technology.

OBJECT: The aim of this research was to evaluate the surgical outcome of a new three-dimensional printing (3DP) technique using prefabrication molds and polymethyl methacrylate (PMMA). PATIENTS AND METHODS: The study included 10 patients with large skull defects (>100 cm2) who underwent cranioplasty. The causes of the skull defects were trauma (6), bone resorption (2), tumor (1), and infection (1). Before the operation, computed tomography (CT) scans were used to create a virtual plan, and these were then converted to 3-dimensional (3-D) images. The field of the skull defect was blueprinted by the technicians and operators, and a prefabricated 3-D model was generated. During the operation, a PMMA implant was created using a prefabricated silicone rubber mold and fitted into the cranial defect. All patients were followed up for at least 2 years, and any complications after the cranioplasty were recorded. RESULTS: Only 1 patient suffered a complication, subdural effusion 2 months after cranioplasty, which was successfully treated with a subdural peritoneal shunt. All patients satisfied the criteria for operative outcome and cosmetic effect. There were no episodes of infection or material rejection. CONCLUSION: The 3DP technology allowed precise, fast, and inexpensive craniofacial reconstruction. This technique may be beneficial for shortening the operation time (and thus reducing exposure time to general anesthesia, and wound exposure time, and blood loss), enhancing preoperative evaluation and simplifying the surgical procedure.

Endoscopic surgery for thalamic hemorrhage: a technical note.

BACKGROUND: Approximately 10% to 15% of cases of ICH involve the thalamus. Evacuation of a thalamic hematoma by craniotomy is associated with high rates of mortality and morbidity. Evacuation by endoscopic surgery is less invasive but is relatively inefficient because of limited visualization of the surgical field. Therefore, a procedure using a polypropylene endoscopic sheath was developed to improve endoscopic visualization and the efficiency of endoscopic evacuation of thalamic hematoma. METHODS: From September 2004 to September 2005, 7 patients underwent endoscopic evacuation of posterial-lateral type thalamic hemorrhage that had ruptured into the lateral ventricle of the trigum and caused acute hydrocephalus. The clinical evaluation included pre- and postoperative Glasgow Coma Scale (GCS) score, 30-day mortality rate, and Glasgow Outcome Scale score 6 months later. The surgical procedure was performed with the patient in the supine position while under general anesthesia. A 3-cm incision was made across the occipital-parietal scalp ipsilateral to the thalamic hematoma. A burr hole, 1 cm in diameter, was drilled on the Keen's point, which is located 3 cm posterior and 3 cm superior to the pinna. A transcortical intraventricular puncture was made with a rigid endoscopic tube. A 2.7-mm endoscope and the necessary surgical instruments were then inserted through this tube, permitting the simultaneous removal of hematoma in the intraventricular space and thalamus. A surgical demonstration of this technique to evacuate thalamic hemorrhage in a patient with acute hydrocephalus is provided herein. RESULTS: The preoperative mean GCS score was 8.4 and the postoperative mean GCS score was 9.4. The 30-day mortality rate was 15% and none of the patients developed shunt-dependent hydrocephalus. The average Glasgow Outcome Scale score was 3.7 six months later. CONCLUSION: Use of a rigid endoscopic sheath in combination with an endoscope and an approach from Keen's point to the collateral trigone of the lateral ventricle improves the efficiency of evacuating thalamic hematomas and prevents shunt-dependent hydrocephalus.

Split-spinous process laminotomy and discectomy for degenerative lumbar spinal stenosis: a preliminary report.

OBJECT: The authors evaluated a new minimally invasive spinal surgery technique to correct degenerative lumbar spinal stenosis involving a split-spinous process laminotomy and discectomy (also known as the "Marmot operation"). METHODS: This prospective study randomized 70 patients with lumbar stenosis to undergo either a Marmot operation (40 patients), or a conventional laminectomy (30 patients), with or without discectomy. Spinal anteroposterior diameter, cross-sectional area, lateral recess distance, spinal stability, postoperative back pain, functional outcomes, and muscular trauma were evaluated. The follow up ranged from 10 to 18 months, with a mean of 15.1 months for the Marmot operation group and 14.8 months for the conventional laminectomy group. Compared with patients in the conventional laminectomy group, patients who received a Marmot operation had a shorter mean postoperative duration until ambulation without assistance, a reduced mean duration of hospital stay, a lower mean creatine phosphokinase-muscular-type isoenzyme level, a lower visual analog scale score for back pain at 1-year follow up, and a better recovery rate. These patients also had a longer mean duration of operative time and a greater mean blood loss compared with the conventional group. Satisfactory neurological decompression and symptom relief were achieved in 93% of these patients. Most of the patients (66%) in this group needed discectomy for decompression. The postoperative mean lateral recess width, spinal anteroposterior diameter, and cross-sectional area were all significantly increased. There was no evidence of spinal instability in any patient. One patient with insufficient lateral recess decompression and recurrent disc herniation needed additional conventional laminectomy and discectomy, and one patient with mild superficial wound infection was successfully treated with antibiotics and frequent dressing changes. CONCLUSIONS: A Marmot operation may provide effective spinal decompression. Although this method requires more operative time than a conventional method, it may involve only minimal muscular trauma, spinal stability maintenance, and early mobilization; shorten the duration of hospital stay; reduce postoperative back pain; and provide satisfactory neurological and functional outcomes.