Comparison of sitting position and prone position for ease of spinal needle insertion in patients undergoing spinal anaesthesia

 

 

Abstract              Background: Position is of paramount importance while giving neuroaxial block to have a successful outcome. The best position is where lumbar lordosis is reduced so as to have better access through interspinous space to reach dura mater. There are few studies which compare sitting position (hamstring stretch position) and prone position. Objective: We compared supine position (hamstring stretch position) vs prone position for performing neuraxial block and hypothesized that there is no difference in reducing the lumber lordosis and needle bone contacts with both positions. Methods: We studied total 120 patients, aged 18-60 years with ASAI and ASAII classification scheduled for elective surgeries under spinal anaesthesia randomized in two groups. Our primary endpoint was the number of spinal needle bone contact and secondary endpoint was ease of needle insertion or space identification. Results: Demographic data was not statistically different between the study groups. Supine (hamstring stretch position) position was found to have less number of needle bone contacts and easier to finding intervertebral space was (P value ‹0.05). Conclusion: there was significant statistical difference between supine and prone position regarding the needle bone contacts and ease of identifying the intervetebral space.

Key words: supine position, prone position, spinal needle, spinal anaesthesia

 

INTRODUCTION

Patient position is very important while administering spinal anaesthesia. Inadequate reversal of lumbar lordosis results in improper position which can lead to back pain, post dural puncture headache, epidural hematoma and neural trauma as well. Most common position for administering spinal anaesthesia is sitting position. Other positions for administering spinal anaesthesia are lateral decubitus and prone position. The aim of any position for spinal anaesthesia is to reverse lumbar lordosis as much as possible so as to have better access through intervertebral space and pushing the thecal sac in more superficial position.² There are several studies which have compared different types of modified sitting positions. In the study by Sussan Soltani Mohammadi et al. in 2016 three modified sitting positions (hamstring stretch position, traditional sitting position and sqatting position) were compared having each group of 120 patients scheduled for elective surgeries under spinal anaesthesia. They found that there is no statistical difference in study groups regarding needle bone contacts and ease of finding interverteberal space although it was found to be easier in traditional sitting position and sqatting position.¹ In a study by Toshayod et al. in 1980 had found hamstring stretch position ( modified sitting position with maximum extension of knees, adduction of hips and forward bending) was found to be more effective in reducing lumbar lordosis and making spinal puncture easier. Even moderate passive extension of knees in sitting position leads to reduction of lumbar lordosis by stretching of hamstrings and increasing its tension.³ Fischer et al. in the year 2009 studied and found both traditional sitting position and hamstring stretch position are equally effective in reducing lumbar lordosis for performing spinal anaesthesia. The number of needle bone contacts were same in both groups.⁴ In another study in the year 2014 by Soltani Mohammadi et al., 230 patients in traditional sitting position were compared with 222 patients in squatting position scheduled for elective lower limb and lower abdominal surgeries. The number of spinal needle-bone contacts were found to be lower in squatting position whereas ease of finding intervertebral space found to be same in both study groups.⁵ Manggala et al. compared the crossed- leg sitting position with traditional sitting position in patients undergoing urologic surgery under spinal anaesthesia, found no significant difference in both study groups in success rate of needle placement and suggested that crossed-leg position can be used as an alternative sitting position for administration of spinal anaesthesia.⁶ We conducted a double blind study to compare hamstring stretch sitting position (HSP) and prone position (PP) to study which position can effectively reduce spinal needle bone contact and by reducing lumbar lordosis improve space identification. Our primary aim was to minimize spinal needle bone contact and secondary aim was finding ease of needle insertion or identifying intervertebral space.

 

METHODS AND MATERIALS

This study was conducted at government medical college and superspeciality hospital Nagpur in 2019-2020, urology surgical operation theatre. A study protocol was given ethical committee approval by local ethics committee.

During preanaesthestic assessment patients were informed regarding proposed position for the procedure. Both positions were explained to patients. A written informed consent was obtained earlier before the procedure with likely risks and complications explained in detail. A total of 120 patients are studied. Patients were divided in two groups each having 60 patients.

Group HSP – Hamstring stretch position

Group PP -Prone position

INCLUSION CRITERIA

1. Patients age between 18-60 years
2. Gender either male or female
3.  Patients with ASA physical status I and II
4. Patients scheduled for elective urologic surgeries under spinal anaesthesia

EXCLUSION CRITERIA:

1. Patients refusing to participate
2. Any history of allergy or hypersensitivity to local anaesthetics
3. Any contraindication to neuraxial block
4. Pregnancy
5. History of lumbar spine surgery/ scar
6. Patients with spine deformities
7. BMI ≥35

 

Randomization was done by lottery method, the name of the position was conceled in covered envelopes opened by the block performer before the spinal procedure. After confirming the patient and surgery, patient is taken inside the operation theatre. An intravenous access is established under sterile precautions. an intravenous isotonic saline was given 3ml/kg and injection fentanyl 50 micrograms given as premedication before performing spinal anaesthesia. ASA standard monitors are attached to patients and baseline parameters are recorded. All spinal blocks are perfomed by two experienced anaesthetists who have more than five years of experience after completing their postgraduation degree.

 For hamstring stretch sitting position (figure 1), anaesthesiologist stand by left side of patient and level of the patient table height adjusted to block performers height. Under all aseptic precautions patients back is painted with betadine 10% solution and after 2 minutes wiped out with 2% chlorhexidine . An intervertebral space is identified by inspection and palpatory method and either of L3-L4 or L2-L3 intervertebral space is chosen. 2ml of 2% lignocaine is infiltrated in the intervertebral space with 25G needle. This is followed by 25G Quinke’s type spinal needle by midline approach. In the meanwhile, an anaesthesiology resident recorded weight, height and surface landmarks graded by block performer as easy, difficult and impossible to palpate lumbar spinous process while the patient was positioned according to the allocation group. For prone position, patient was asked to lie down on belly with one or two pillows below the belly to achieve maximum possible lumber lordosis reduction. The block performer again stand by left side of the patient and table height is adjusted to comfortable level to the block performer. The spinal procedures were performed to improve needle insertion or space identification and minimize spinal needle-bone contacts. A spinal needle bone contact was defined as spinal needle contact against the bone which prevents further entry of spinal needle. Number of spinal bone contacts were recorded. The study was complete when subarachnoid space was confirmed by observing free flow of Cerebro spinal fluid (CSF). Free flow of CSF was more clearly evident in hamstring stretch position (HSP) but in case of to prone position block performer has to wait for 10-15 seconds or negatively aspirate through the spinal needle so as to observe free CSF coming from the needle. In both study groups, if CSF flow is not free on negative aspiration spinal needle is rotated 90 degrees clockwise and block performer had to wait again for 5 seconds. The sequence of rotation continued for another three quadrant rotation of 90 degrees and wait for 5 seconds after each rotation. If even after this maneuver, no free flow of CSF observed on negative aspiration then spinal needle is advanced by 2mm. the block performer was not allowed to perform new puncture and only allowed to pull back spinal needle just to the subcutaneous tissue. When a bone was encountered in any of the study group patient, the needle was withdrawn just below the skin level and redirected more cephalad angle. If more than 4 spinal needle bone contacts were encountered then case was recorded as failure and the study was stopped.

We classified ease of insertion depending upon the number of needle bone contacts as follows:

1. Easy : upto 2 needle bone contacts
2. Difficult : more than 2 but less than 5 needle bone contacts
3. Impossible : 5 or more needle bone contacts

 

RESULTS

The mean age of patients in HSP group was 41.6 years and 41.8 years in PP group, which was comparable and the difference was not statistically significant. The mean weight of the patients in study group HSP was 64.74 kgs and in group PP was 62.93 kgs which was comparable and difference was not statistically significant.

Data was analyzed and compared.

 

 

 

 

 

 

 

 

 

Policy for Articles with Open Access:

Authors who publish with MedPulse International Journal of Pediatrics (Print ISSN: 2579-0897) (Online ISSN: 2636-4662) agree to the following terms: Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.

Authors are permitted and encouraged to post links to their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work.