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: Coccydynia is pain in the coccyx that typically occurs idiopathically or from trauma. Most forms are self-limiting. However, if symptoms persist, nonsurgical treatment options can include offloading, NSAIDs, physical therapy, and steroid injections. If all treatment options fail, a growing body of evidence supports a coccygectomy for symptomatic relief. The standard approach for a coccygectomy involves a midline incision cephalad to the anus along the gluteal cleft. Historically, this method has had high rates of infection.
OBJECTIVE: To improve healing and decrease infection rate, we propose the paramedian approach to a coccygectomy. This approach has the benefit of distancing the surgical site from the anus, diminishing the crevice effect of the incision, and increasing the dermal and subdermal thickness for improved surgical closure.
METHODS: We present a case series study of 41 patients who underwent the paramedian approach coccygectomy using a 4 to 6 cm incision, approximately 0.5 to 1.5 cm lateral to the midline, for coccyx removal. These patients were evaluated postoperatively to determine infection rate and various outcome measures.
METHODS: Forty-one patients suffering from refractory coccydynia had a coccygectomy via the paramedian approach between 2011 and 2022 by the senior author.
METHODS: Outcome measures included self-reported measures (Oswestry Disability Index (ODI), Visual Analogue Scale (VAS) pain scale and satisfaction with procedure), physiologic measures (presence of infection and treatment provided) and functional measures (return to vocation/avocation).
METHODS: Data was compiled and transferred to Microsoft Excel and analyzed. Two-tailed T-tests were used to compare the patient improvement in VAS and ODI as appropriate for statistical analysis.
RESULTS: The patients\' average age was 45.8 years. Patients\' average body mass index was 27.9, with 71% of patients overweight or obese. A total of 68% of patients were female. Trauma was the most common precipitating factor (75.6%). Five patients presented with postoperative complications (12.1%), one requiring an incision and drainage, and four others were treated with antibiotics for wound erythema. Postoperative evaluations showed continual improvement, with the most significant improvement reported greater than 1-year postoperatively. The Visual Analogue Scale for pain dropped from 7.5 to 2.3 (p<.001), and the Oswestry Disability Index improved from 30.1 to 9.6 (p<.001). A total of 86.7% of patients reported either a good or excellent result.
CONCLUSIONS: Coccygectomies via the midline approach have a variable infection rate, likely due to proximity of the incision to the anus and due to the crevice effect of the gluteal cleft in terms of aeration. These contributing factors are overcome in the paramedian approach, making it an effective option for treating refractory coccydynia that is nonresponsive to conservative management.

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.

BACKGROUND: The development of back pain following epidural analgesia is one reason for patient refusal of neuraxial analgesia. The primary endpoint of this study was to compare the incidence and severity of back pain following midline and paramedian epidural technique. The secondary endpoint was to identify the risk factors associated with the occurrence of back pain.
METHODS: This prospective randomized study included 114 patients receiving thoracic epidural catheterization for pain management following upper abdominal or thoracic surgery. Patients were allocated to either the midline or the paramedian group by computer-generated randomization. An investigator who was blinded to the patient group interviewed patients at 24, and 48 h, and 3-5 days after surgery about the existence of back pain and its severity.
RESULTS: The total incidence of back pain following epidural anesthesia was 23.8% in the midline group and 7.8% in the paramedian group. The numerical rating scale of back pain was not different between the two groups at 24 h and 4 days after surgery. The paramdian technique was associated with a lower incidence of back pain than the midline technique (95% confidence interval 0.05-0.74, odds ratio 0.2, P < 0.01). However, the number of attempts, surgical position, body mass index, and duration of surgery were not associated with back pain.
CONCLUSIONS: This study showed that the midline group of thoracic epidural analgesia demonstrated higher incidence of back pain than the paramedian group. However, the pain was mild in intensity and decreased with time in both groups.

Midline and paramedian mandibulotomies both have distinct anatomical and surgical strengths. A retrospective study was performed at Chang Gung Memorial Hospital, Linkou Branch between 2014 and 2019 to investigate how the osteotomy site (midline (n = 221) or paramedian (n = 44)) and type (straight, notched, or stair-stepped) affect postoperative and post-radiotherapy complications in patients undergoing wide excision of tongue cancer with flap reconstruction. Midline mandibulotomies were predominantly of the straight osteotomy type, while paramedian mandibulotomies were mostly notched type (P < 0.001). Comparably low elective tooth extraction rates were found in both approaches (P = 0.556). Paramedian mandibulotomy showed a higher osteoradionecrosis rate (P = 0.026), but there was no significance in the sub-analysis of individual types. Paramedian sites were associated with more early infection (P = 0.036) and plate exposure (P = 0.036) than midline sites with the straight osteotomy type, but complication rates did not differ significantly for the notched and stair-stepped types. Paramedian sites (P = 0.020) and notched types (P = 0.006) were associated with higher odds of osteoradionecrosis in the univariable logistic regression analysis, but only the notched type remained significant in the multivariable analysis (P = 0.048). In conclusion, paramedian sites increased the rate of osteoradionecrosis, and correlation with the osteotomy type resulted in more osteoradionecrosis in notched types and more complications in straight paramedian mandibulotomies.

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. In this study, we discuss imaging the patterns of AOP infarction and its differentials and clinical presentation.

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.