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"NIMS technique" for minimally invasive spinal fixation using non-fenestrated pedicle screws: A technical note.

Rajesh A, Pelluru PK, Kumar A - J Craniovertebr Junction Spine (2015 Oct-Dec)

Bottom Line: All patients were mobilized the very next day after confirming the position of implants on X-ray/computed tomography.At the end of 1-year follow-up, we had two cases of screw cap loosening and with a displacement of the rod cranio-caudally in one case which was revised through the same incisions.This may extend the benefits to a lower socioeconomic group who cannot afford the cost of fenestrated screw (FS).

View Article: PubMed Central - PubMed

Affiliation: Department of Neurosurgery, Nizam's Institute of Medical Sciences, Hyderabad, Telangana, India.

ABSTRACT

Study design: Case series.

Objective: To reduce the cost of minimally invasive spinal fixation.

Background: Minimally invasive spine (MIS) surgery is an upcoming modality of managing a multitude of spinal pathologies. However, in a resource-limited situations, using fenestrated screws (FSs) may prove very costly for patients with poor affordability. We here in describe the Nizam's Institute of Medical Sciences (NIMS) experience of using routine non-FSs (NFSs) for transpedicular fixation by the minimally invasive way to bridge the economic gap.

Materials and methods: A total of 7 patients underwent NFS-minimally invasive spine (MIS) surgery. Male to female distribution was 6:1. The average blood loss was 50 ml and the mean operating time was 2 and 1/2 h. All patients were mobilized the very next day after confirming the position of implants on X-ray/computed tomography.

Results: All 7 patients are doing well in follow-up with no complaints of a backache or fresh neurological deficits. There was no case with pedicle breach or screw pullout. The average cost of a single level fixation by FS and NFS was ₹1, 30,000/patient and ₹32,000/patient respectively ('2166 and '530, respectively). At the end of 1-year follow-up, we had two cases of screw cap loosening and with a displacement of the rod cranio-caudally in one case which was revised through the same incisions.

Conclusions: Transpedicular fixation by using NFS for thoracolumbar spinal pathologies is a cost-effective extension of MIS surgery. This may extend the benefits to a lower socioeconomic group who cannot afford the cost of fenestrated screw (FS).

No MeSH data available.


Related in: MedlinePlus

Tapping of the proposed screw trajectory over a guidewire
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Figure 4: Tapping of the proposed screw trajectory over a guidewire

Mentions: The patients were operated in prone position, rested over bolsters with padding over the pressure points and lax abdomen. The levels of surgery were marked using fluoroscopy [Figure 1]. The pedicle entry points were identified on true anteroposterior (AP) view. The skin was incised with a stab and pedicles were tapped with pedicle access kit from the lateral pedicular margin until it reached the medial margin of pedicle in AP view. The position of the tip was then confirmed on lateral view to have crossed the pedicle-body junction [Figure 2]. After confirming the same, the needle was advanced further and was threaded with a guide wire. The pedicle needle was removed keeping the guide wire in situ. The soft tissue track was dilated with serial dilators [Figure 3]. With the last dilator and guidewire in situ, the pedicle and body were tapped with FS driver of diameter 5 mm less than that of the intended screw thickness. This was done as a precautionary measure to have a tight but still negotiable track. The screwdriver and the dilator were removed and the trajectory and the angle were observed. Until this point the procedure is the same as any standard minimally invasive pedicle screw fixation. The guide wire is the removed and an NFS is threaded into the pedicle hole along the trajectory [Figure 4]. The guiding forces for correct placement of the screw without the guidewire were the fluoroscopy in lateral view and the bony tactile sensation while threading the screw (Note: The very interesting finding we noticed serendipitously was that with the narrow path created directly over the pedicle entry point, there is no place for a screw to go except for the path created. It is something akin to single key slot in the door which can only take in the key). We used fixed angle screws which were coded externally for the direction of the hub for rod placement. Percutaneous tunneling was done and the connecting rod en routed through the subcutaneous tunnel, using free hand technique [Figure 5]. Screw caps were placed under direct visualization. For reduction, manual pressure was applied over the affected spinous process by the assistant and the screw caps were tightened simultaneously on one side, each acting as counter-torq for the other. Postoperative X-ray/computed tomography was used to confirm the position of the hardware [Figures 6 and 7]. The radiation exposure was approximately 90 shots (2 min, 15 s) which have to be taken into account and can be reduced.


"NIMS technique" for minimally invasive spinal fixation using non-fenestrated pedicle screws: A technical note.

Rajesh A, Pelluru PK, Kumar A - J Craniovertebr Junction Spine (2015 Oct-Dec)

Tapping of the proposed screw trajectory over a guidewire
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4660491&req=5

Figure 4: Tapping of the proposed screw trajectory over a guidewire
Mentions: The patients were operated in prone position, rested over bolsters with padding over the pressure points and lax abdomen. The levels of surgery were marked using fluoroscopy [Figure 1]. The pedicle entry points were identified on true anteroposterior (AP) view. The skin was incised with a stab and pedicles were tapped with pedicle access kit from the lateral pedicular margin until it reached the medial margin of pedicle in AP view. The position of the tip was then confirmed on lateral view to have crossed the pedicle-body junction [Figure 2]. After confirming the same, the needle was advanced further and was threaded with a guide wire. The pedicle needle was removed keeping the guide wire in situ. The soft tissue track was dilated with serial dilators [Figure 3]. With the last dilator and guidewire in situ, the pedicle and body were tapped with FS driver of diameter 5 mm less than that of the intended screw thickness. This was done as a precautionary measure to have a tight but still negotiable track. The screwdriver and the dilator were removed and the trajectory and the angle were observed. Until this point the procedure is the same as any standard minimally invasive pedicle screw fixation. The guide wire is the removed and an NFS is threaded into the pedicle hole along the trajectory [Figure 4]. The guiding forces for correct placement of the screw without the guidewire were the fluoroscopy in lateral view and the bony tactile sensation while threading the screw (Note: The very interesting finding we noticed serendipitously was that with the narrow path created directly over the pedicle entry point, there is no place for a screw to go except for the path created. It is something akin to single key slot in the door which can only take in the key). We used fixed angle screws which were coded externally for the direction of the hub for rod placement. Percutaneous tunneling was done and the connecting rod en routed through the subcutaneous tunnel, using free hand technique [Figure 5]. Screw caps were placed under direct visualization. For reduction, manual pressure was applied over the affected spinous process by the assistant and the screw caps were tightened simultaneously on one side, each acting as counter-torq for the other. Postoperative X-ray/computed tomography was used to confirm the position of the hardware [Figures 6 and 7]. The radiation exposure was approximately 90 shots (2 min, 15 s) which have to be taken into account and can be reduced.

Bottom Line: All patients were mobilized the very next day after confirming the position of implants on X-ray/computed tomography.At the end of 1-year follow-up, we had two cases of screw cap loosening and with a displacement of the rod cranio-caudally in one case which was revised through the same incisions.This may extend the benefits to a lower socioeconomic group who cannot afford the cost of fenestrated screw (FS).

View Article: PubMed Central - PubMed

Affiliation: Department of Neurosurgery, Nizam's Institute of Medical Sciences, Hyderabad, Telangana, India.

ABSTRACT

Study design: Case series.

Objective: To reduce the cost of minimally invasive spinal fixation.

Background: Minimally invasive spine (MIS) surgery is an upcoming modality of managing a multitude of spinal pathologies. However, in a resource-limited situations, using fenestrated screws (FSs) may prove very costly for patients with poor affordability. We here in describe the Nizam's Institute of Medical Sciences (NIMS) experience of using routine non-FSs (NFSs) for transpedicular fixation by the minimally invasive way to bridge the economic gap.

Materials and methods: A total of 7 patients underwent NFS-minimally invasive spine (MIS) surgery. Male to female distribution was 6:1. The average blood loss was 50 ml and the mean operating time was 2 and 1/2 h. All patients were mobilized the very next day after confirming the position of implants on X-ray/computed tomography.

Results: All 7 patients are doing well in follow-up with no complaints of a backache or fresh neurological deficits. There was no case with pedicle breach or screw pullout. The average cost of a single level fixation by FS and NFS was ₹1, 30,000/patient and ₹32,000/patient respectively ('2166 and '530, respectively). At the end of 1-year follow-up, we had two cases of screw cap loosening and with a displacement of the rod cranio-caudally in one case which was revised through the same incisions.

Conclusions: Transpedicular fixation by using NFS for thoracolumbar spinal pathologies is a cost-effective extension of MIS surgery. This may extend the benefits to a lower socioeconomic group who cannot afford the cost of fenestrated screw (FS).

No MeSH data available.


Related in: MedlinePlus