BACKGROUND: A side effect of spinal anesthesia is post-dural puncture backache (PDPB), which is characterized by ongoing discomfort at the location of the spinal puncture without any radicular pain. This study aims to compare the incidence and severity of post-dural puncture back pain following spinal anesthesia by median versus paramedian technique in obese female patients.
METHODS:  A prospective randomized comparative study on 120 female patients, aged 20-50 years with a BMI of 30-40 kg/m2 and American Society of Anesthesiologists physical status II, scheduled for elective surgery under spinal anesthesia, was included in the study. Patients were randomly divided into two groups, with 60 patients in each group. Group P uses the paramedian approach for spinal anesthesia, and group M uses the midline approach for spinal anesthesia.
RESULTS: Low back pain incidence was lower in group P than in group M at seven days, but at one month and after, its incidence remained the same in both groups. No difference in the severity of pain was observed.
CONCLUSIONS: The occurrence of back pain in the first seven days of surgery was significantly more frequent with the median approach. The pain severity decreased as the time passed from day seven to three months of follow-up. There is no difference in the severity of pain with either approach at different intervals.

BACKGROUND: Pre-procedural ultrasound can be used to identify the subarachnoid space in difficult spinal procedures. However, multiple punctures can result in numerous complications, including post-dural puncture headache, neural trauma, and spinal and epidural haematoma. Thus, the following hypothesis was proposed: in contrast to the conventional blind paramedian dural puncture, pre-procedural ultrasound results in a successful dural puncture on the first attempt.
METHODS: In this prospective, randomised controlled study, 150 consenting patients were randomly assigned to one of the two groups: ultrasound-guided paramedian (UG) and conventional blind paramedian (PG). In the UG paramedian group, pre-procedural ultrasound was performed to mark the insertion site, whereas, in the PG group, the landmark technique was used. A total of 22 different anaesthesiology residents performed all subarachnoid blocks.
RESULTS: The time taken to perform spinal anaesthesia in the UG group was 38-49.5 s, which is shorter than the time taken in the PG group, which was 38-55 s, with a p-value < 0.046, which is statistically significant. The primary outcome of a successful dural puncture on the first attempt was not significantly higher in the UG group (49.33%) than in the PG group (34.67%), with a p-value < 0.068. The number of attempts taken for a successful spinal tap in the UG group was a median of 2.0 (1 to 2), and the PG group had a median of 2 (1 to 2.5), with a p-value < 0.096, which is statistically non-significant.
CONCLUSIONS: Ultrasound guidance showed improvement in the success rate of paramedian anaesthesia. In addition, it improves the success rate of dural puncture and the rate of puncture on the first attempt. It also shortens the time required for a dural puncture. In the general population, the pre-procedural UG paramedian group did not outperform the PG paramedian group.

UNASSIGNED: Vertical Paramedian Hemispherotomy (VPH) is considered an effective surgical treatment for drug-resistant epilepsy with 80% of patients experiencing seizure freedom or worthwhile improvement. Identifying persistent connective tracts is challenging in failed VPH.
UNASSIGNED: We reviewed our series of consecutive patients undergoing VPH for hemispheric drug-resistant epilepsy and included cases with recurrent epileptic seizures undergoing second surgery with at least 6 months of postoperative follow-up. The cases were extensively assessed to propose a targeted complementary resection.
UNASSIGNED: Two children suffering from seizure recurrence following hemispherotomy leading to second surgery were included. After complete assessment, persisting amygdala residue was suspected responsible for the epilepsy recurrence in both patients. Complementary resection of the amygdala residue led to seizure freedom for both patients (Engel IA/ILAE Class 1) without complication. Different diagnostic tools are used to assess patients after failed hemispherotomy including routine EEG, prolonged video EEG, MRI (particularly DTI sequences), SPECT or PET scans and clinical evaluation. These tools allow to rule out epileptic foci in the contralateral hemisphere and to localize a potentially persisting epileptogenic zone. Assessment of these patients should be as systematic and integrated as the initial workup. Although our two patients suffered from Rasmussen\'s encephalitis, seizure recurrence after VPH has been described in other pathologies.
UNASSIGNED: Lying deep and medially in the surgical corridor of VPH, the amygdala can be incompletely resected and cause recurrent epilepsy. Complementary selective resection of the amygdala residue may safely lead to success in epilepsy control.

Epidermoid cysts of the pineal region are a rare entity. Herein, the authors describe the endoscopic resection of a recurrent pineal region epidermoid by way of a supracerebellar infratentorial approach. The patient was positioned in the semiseated upright position with head tilted to the right and slightly flexed, maximizing gravity-based cerebellar retraction, and a paramedian craniotomy was performed owing to the gradual flattening of the tentorium from medial to lateral. This setup, in tandem with the enlarged viewing window achieved by use of 0°, 30°, and 70° endoscopes, afforded the necessary access to achieve a satisfactory resection through this anatomical corridor. The video can be found here: https://stream.cadmore.media/r10.3171/2021.4.FOCVID2131.

UNASSIGNED: The endoscopic supracerebellar-infratentorial (SCIT) approach is a viable method to access pathology of the posterior incisura, but a narrow working space and frequent instrument conflict can potentially limit its surgical efficacy. We planned an endoscopic-assisted paramedian infratentorial supracerebellar approach for pineal cyst.
UNASSIGNED: Patient was placed in prone position under general anesthesia. His head was rotated to the left side slightly. The location of the transverse sinus was detected with navigation system. A 5 cm linear skin incision was performed, and a 2 cm craniectomy was performed about 2 cm left of the median. The transverse sinus was little bit exposed. Dura was incised in a U-shaped incision with the transverse sinus at the base. The endoscope was advanced along with the culmen. At that time, we observed inferior and superior vermian vein. After reaching to the thick arachnoid near by galenic system, the arachnoid membrane was incised and the CSF was evacuated. After that, the cerebellum became soft and the surgical corridor became large. The arachnoid membrane was incised widely. Pineal cyst, precentral cerebellar vein, bilateral internal occipital vein and great vein of galen were exposed. There were some small veins on the pineal cyst, but the adhesion was not so severe. The cyst was dissected from these small veins. There was no adhesion between the cyst and surrounding brain except for the pineal recess. Bilateral ICV was seen behind the cyst. There was feeding artery and draining vein on the antero-lateral part of the cyst. These vessels were coagulated and cut, then the cyst was removed. After the removal, we confirmed complete removal of the cyst and hemostasis.
UNASSIGNED: Endoscopic-assisted paramedian SCIT approach for pineal cyst in prone position is a reasonable and efficient access for posterior third ventricular lesions. The learning curve, maneuverability in small space, and instrument conflict limit efficacy.

The Artery of Percheron (AOP) is an uncommon anatomic variant that provides arterial supply to the paramedian region of the thalami and bilaterally to the rostral part of the midbrain; it is a solitary arterial trunk that branches from a proximal segment of the posterior cerebral artery (PCA). Although AOP infarction results in a characteristic pattern of ischemia, namely bilateral paramedian thalamic infarct with or without midbrain involvement, it may cause diagnostic difficulties due to the variety of its clinical presentations and wide differentials, as well as its small diameter and the difficulty of obtaining visualization through diagnostic imaging. Early neuroimaging of AOP infarction and correct diagnosis are mandatory for early initiation of the appropriate treatment and better patient outcomes. This study discusses the imaging patterns and imaging differentials of AOP infarction and its clinical presentation. A 55-year-old man presented to the emergency department unconscious with Glasgow Coma Scale score of 4. Pupillary light reflex on both eyes was poorly reactive with dilatated right pupil. The patient flexed his arm and extended his leg on painful stimulus. Laboratory tests and electrocardiogram were unremarkable. Emergency cerebral CT scan and transcranial Doppler ultrasound were normal. He gradually regained consciousness with residual somnolence, ptosis, and vertical gaze palsy. Second CT scan showed bilateral paramedian thalamic areas of hypodensity, CT angiography (CTA) was unremarkable. MRI showed bilateral high-signal intensity on paramedian thalami fast spin echo T2, FLAIR, and diffusion-weighted sequences, low signal on apparent diffusion coefficient sequence. MR angiography (MRA) revealed an abnormal tiny vessel arising from the P1 segment of the left posterior cerebral artery. Imaging findings were consistent with AOP infarction. Aspirin was started, 4 hours after admission the patient regained consciousness, and gradually improved on the following days till he was discharged on the 15th day, with mild neurologic deficit. AOP must be considered whenever paramedian thalamic infarction is noted in neuroimaging. The difficulty in visualizing the AOP using diagnostic imaging is due to its small diameter, leading to the limited abilities of MRA and CTA to diagnose AOP infarction. An absence of evidence of AOP infarction in MRA or even CTA does not exclude its diagnosis. Good knowledge of the imaging characteristics of AOP infarction will help in early diagnosis and the achievement of good patient outcomes.

OBJECTIVE: This study aimed to compare the influences of postoperative oral function in patients with median or paramedian mandibulotomy during the radical resection of tongue carcinoma and to provide evidence for the choice of osteotomy location for mandibulotomy.
METHODS: The clinical data of 126 patients who underwent combined radical neck dissection with mandibulectomy and glossectomy followed by simultaneous reconstruction were analyzed retrospectively. The patients were divided into two groups according to the position of mandibulotomy: median mandibulotomy group (median group, n=60) and paramedian mandibulotomy group (paramedian group, n=66). The fourth edition of the University of Washington Quality of Life Questionnaire (UW-QOL) was used to compare the differences in oral functions, such as swallowing, mastication, and speech, between the two groups during regular follow-up. SPSS 24.0 software package was used for statistical analysis, and P<0.05 was considered statistically significant.
RESULTS: Six months after the operation, no significant differences in swallowing, mastication, and speech functions were found between the median and paramedian groups. However, the swallowing and speech functions in the paramedian group were better than those in the median group 1 year after the operation (P<0.05), whereas no statistical difference in mastication function was observed between the two groups.
CONCLUSIONS: Evaluation of the postoperative oral function results showed that paramedian mandibulotomy was a better surgical approach than median mandibulotomy. Paramedian mandibulotomy is worth prioritizing in the radical resection of tongue carcinoma.
目的 比较正中或旁正中下颌骨截骨术对舌癌患者口腔功能的影响，为下颌骨截骨位置的选择提供依据。方法 回顾性分析经下颌骨截骨入路进行舌颌颈联合根治及缺损修复重建的126例舌癌患者的临床资料。根据截开下颌骨位置的不同，分为下颌骨正中截骨术组（正中组，n=60）和下颌骨旁正中截骨术组（旁正中组，n=66）。术后定期随访，应用华盛顿大学生存质量问卷（UW-QOL）第四版比较2组患者术后吞咽、咀嚼和语音等口腔功能的差异。采用SPSS 24.0软件包进行统计学处理，P<0.05为差异有统计学意义。结果 术后6月，正中组与旁正中组吞咽、咀嚼及语音功能评分差异均无统计学意义；术后1年，旁正中组患者吞咽和语音功能评分优于正中组（P<0.05），但咀嚼功能评分差异无统计学意义。结论 经旁正中下颌骨截骨入路进行舌颌颈联合根治，术后患者口腔功能优于经正中下颌骨截骨入路。.

The high versatility and efficacy of the contralateral interhemispheric approach is demonstrated in this resection of an arteriovenous malformation (AVM). This patient had a large AVM along the medial frontal lobe amenable to approach via the contralateral interhemispheric approach. The head was rotated to permit gravity retraction of the ipsilateral hemisphere to the AVM, avoiding the use of rigid retractors. Under the guidance of neuronavigation, the falx was opened to permit visualization of the AVM. Circumdissection with a disconnection of the nidus was performed in a standard fashion. Postoperative angiography confirmed complete removal of the AVM. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Developing new surgical instruments is challenging. While making surgical instruments could be a good field of application for 3D printers, attempts to do so have proven limited. We designed a new endoscope-assisted spine surgery system, and using a 3D printer, attempted to create a complex surgical instrument and to evaluate the feasibility thereof. Developing the new surgical instruments using a 3D printer consisted of two parts: one part was the creation of a prototype instrument, and the other was the production of a patient model. We designed a new endoscope-assisted spine surgery system with a cannula for the endoscope and working instruments and extra cannula that could be easily added. Using custom-made patient-specific 3D models, we conducted discectomies for paramedian and foraminal discs with both the newly designed spine surgery system and conventional tubular surgery. The new spine surgery system had an extra portal that can be well bonded in by a magnetic connector and greatly expanded the range of access for instruments without unnecessary bone destruction. In foraminal discectomy, the newly designed spine surgery system showed less facet resection, compared to conventional surgery. We were able to develop and demonstrate the usefulness of a new endoscope-assisted spine surgery system relying on 3D printing technology. Using the extra portal, the usability of endoscope-assisted surgery could be greatly increased. We suggest that 3D printing technology can be very useful for the realization and evaluation of complex surgical instrument systems.

OBJECTIVE: Routine use of pre-procedural ultrasound guided midline approach has not shown to improve success rate in administering subarachnoid block. The study hypothesis was that the routine use of pre-procedural (not real time) ultrasound-guided paramedian spinals at L5-S1 interspace could reduce the number of passes (i.e., withdrawal and redirection of spinal needle without exiting the skin) required to enter the subarachnoid space when compared to the conventional landmark-guided midline approach.
METHODS: After local ethics approval, 120 consenting patients scheduled for elective total joint replacements (Hip and Knee) were randomised into either Group C where conventional midline approach with palpated landmarks was used or Group P where pre-procedural ultrasound was used to perform subarachnoid block by paramedian approach at L5-S1 interspace (real time ultrasound guidance was not used).
RESULTS: There was no difference in primary outcome (difference in number of passes) between the two groups. Similarly there was no difference in the number of attempts (i.e., the number of times the spinal needle was withdrawn from the skin and reinserted). The first pass success rates (1 attempt and 1 pass) was significantly greater in Group C compared to Group P [43% vs. 22%, P = 0.02].
CONCLUSIONS: Routine use of paramedian spinal anaesthesia at L5-S1 interspace, guided by pre-procedure ultrasound, in patients undergoing lower limb joint arthroplasties did not reduce the number of passes or attempts needed to achieve successful dural puncture.